Examples with solutions for Solving an Equation by Multiplication/ Division: Using fractions

Exercise #1

Find the value of the parameter X

13x=19 \frac{1}{3}x=\frac{1}{9}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Identify the given fraction equation.
  • Multiply both sides of the equation by the reciprocal of the coefficient of x x .
  • Simplify to isolate x x .

Now, let's work through these steps:
Step 1: The problem gives us the equation 13x=19 \frac{1}{3} x = \frac{1}{9} .
Step 2: We multiply both sides by 3 to eliminate the fraction on the left side:

3×13x=3×19 3 \times \frac{1}{3} x = 3 \times \frac{1}{9}

Step 3: Simplifying both sides results in:

x=39 x = \frac{3}{9}

Further simplification of 39\frac{3}{9} yields:

x=13 x = \frac{1}{3}

Therefore, the solution to the problem is 13 \frac{1}{3} .

Answer

13 \frac{1}{3}

Exercise #2

y5=25 \frac{-y}{5}=-25

Video Solution

Step-by-Step Solution

We begin by multiplying the simple fraction by y:

15×y=25 \frac{-1}{5}\times y=-25

We then reduce both terms by 15 -\frac{1}{5}

y=2515 y=\frac{-25}{-\frac{1}{5}}

Finally we multiply the fraction by negative 5:

y=25×(5)=125 y=-25\times(-5)=125

Answer

y=125 y=125

Exercise #3

Solve the equation

312y=21 3\frac{1}{2}\cdot y=21

Video Solution

Step-by-Step Solution

To solve the equation 312y=21 3\frac{1}{2} \cdot y = 21 , we'll follow these steps:

  • Convert the mixed number to an improper fraction.
  • Divide both sides of the equation by the coefficient of y y .

Let's analyze these steps in detail:

Step 1: Convert the mixed number to an improper fraction.
The coefficient of y y is 312 3\frac{1}{2} . Converting to an improper fraction, we have:

312=72 3\frac{1}{2} = \frac{7}{2}

Step 2: Divide both sides of the equation by 72 \frac{7}{2} .
The equation becomes:

72y=21 \frac{7}{2} \cdot y = 21

To isolate y y , divide both sides by 72 \frac{7}{2} :

y=21÷72 y = 21 \div \frac{7}{2}

Dividing by a fraction is equivalent to multiplying by its reciprocal, so:

y=2127 y = 21 \cdot \frac{2}{7}

Carrying out the multiplication, we calculate:

y=2127=427 y = \frac{21 \cdot 2}{7} = \frac{42}{7}

Dividing the numerator by the denominator gives us:

y=6 y = 6

Thus, the solution to the equation is y=6 y = 6 .

Answer

y=6 y=6

Exercise #4

Solve for X:

28x3=7 \frac{2}{8}x-3=7

Video Solution

Step-by-Step Solution

To solve the equation 28x3=7 \frac{2}{8}x - 3 = 7 , we'll follow these steps:

  • Step 1: Simplify the fraction. The coefficient 28 \frac{2}{8} simplifies to 14 \frac{1}{4} .
  • Step 2: Eliminate the constant term by adding 3 to both sides of the equation.
  • Step 3: Solve for x x by removing the coefficient of x x using division.

Let's solve the equation step-by-step:

Step 1: Simplify the equation:
The equation 28x3=7 \frac{2}{8}x - 3 = 7 simplifies to 14x3=7 \frac{1}{4}x - 3 = 7 .

Step 2: Eliminate the constant term:
Add 3 to both sides to isolate the term involving x x :

14x3+3=7+3\frac{1}{4}x - 3 + 3 = 7 + 3

This simplifies to:

14x=10\frac{1}{4}x = 10

Step 3: Solve for x x :
Multiply both sides by the reciprocal of 14 \frac{1}{4} to solve for x x :

414x=4104 \cdot \frac{1}{4}x = 4 \cdot 10

This simplifies to:

x=40x = 40

Therefore, the solution to the equation is x=40 x = 40 .

Answer

40

Exercise #5

Solve for X:

15x4=6 \frac{1}{5}x-4=6

Video Solution

Step-by-Step Solution

To solve the equation 15x4=6\frac{1}{5}x - 4 = 6, we will follow these steps:

  • Step 1: Add 4 to both sides of the equation to eliminate the subtraction and isolate the fractional term.
  • Step 2: Multiply both sides by 5 to clear the fraction and solve for x x .

Let's apply these steps to solve the equation:

Step 1: Add 4 to both sides:
15x4+4=6+4 \frac{1}{5}x - 4 + 4 = 6 + 4
This simplifies to:
15x=10 \frac{1}{5}x = 10

Step 2: Multiply both sides by 5 to solve for x x :
5×15x=10×5 5 \times \frac{1}{5}x = 10 \times 5
This simplifies to:
x=50 x = 50

Therefore, the solution to the equation is x=50 x = 50 .

Answer

50

Exercise #6

x4+2x18=0 \frac{x}{4}+2x-18=0

x=? x=\text{?}

Video Solution

Step-by-Step Solution

To solve the equation x4+2x18=0\frac{x}{4} + 2x - 18 = 0, we proceed as follows:

  • Step 1: Eliminate the fraction by multiplying the entire equation by 4:
    (4)(x4+2x18)=(4)(0)(4) \Big(\frac{x}{4} + 2x - 18\Big) = (4)(0)
  • Step 2: Distribute and simplify:
    x+8x72=0x + 8x - 72 = 0
  • Step 3: Combine like terms:
    9x72=09x - 72 = 0
  • Step 4: Isolate 9x9x by adding 72 to both sides:
    9x=729x = 72
  • Step 5: Solve for xx by dividing both sides by 9:
    x=729x = \frac{72}{9}
  • Step 6: Simplify the division:
    x=8x = 8

Thus, the solution to the problem is x=8x = 8.

Answer

8

Exercise #7

3b=76 3b=\frac{7}{6}

Video Solution

Step-by-Step Solution

To solve the equation 3b=76 3b = \frac{7}{6} for the variable b b , we will perform the following steps:

  • Step 1: Identify the equation. The given equation is 3b=76 3b = \frac{7}{6} .
  • Step 2: Isolate the variable. Divide both sides by 3 to solve for b b .

When we divide both sides of the equation by 3, we obtain:

b=763 b = \frac{\frac{7}{6}}{3}

Step 3: Simplify the expression. Dividing a fraction by an integer is equivalent to multiplying the denominator of the fraction by that integer:

b=76×3 b = \frac{7}{6 \times 3}

The denominator becomes:

b=718 b = \frac{7}{18}

Thus, the solution to the equation is b=718 b = \frac{7}{18} .

This matches the correct answer choice among the given options.

Therefore, the value of b b is b=718 b = \frac{7}{18} .

Answer

b=718 b=\frac{7}{18}

Exercise #8

3x4=16 \frac{3x}{4}=16

Video Solution

Step-by-Step Solution

To solve the equation 3x4=16\frac{3x}{4} = 16, we will eliminate the fraction by multiplying both sides by 4.

  • Step 1: Multiply both sides by 4:
    (3x4)×4=16×4\left(\frac{3x}{4}\right) \times 4 = 16 \times 4
  • Step 2: Simplify:
    3x=643x = 64
  • Step 3: Solve for xx by dividing both sides by 3:
    x=643x = \frac{64}{3}
  • Step 4: Simplify the fraction to a mixed number:
    x=2113x = 21\frac{1}{3}

Therefore, the solution to the equation 3x4=16\frac{3x}{4} = 16 is x=2113 x = 21\frac{1}{3} .

Answer

x=2113 x=21\frac{1}{3}

Exercise #9

Find the value of the parameter X

13x+56=16 \frac{1}{3}x+\frac{5}{6}=-\frac{1}{6}

Video Solution

Step-by-Step Solution

First, we will arrange the equation so that we have variables on one side and numbers on the other side.

Therefore, we will move 56 \frac{5}{6} to the other side, and we will get

13x=1656 \frac{1}{3}x=-\frac{1}{6}-\frac{5}{6}

Note that the two fractions on the right side share the same denominator, so you can subtract them:

13x=66 \frac{1}{3}x=-\frac{6}{6}

Observe the minus sign on the right side!

13x=1 \frac{1}{3}x=-1

Now, we will try to get rid of the denominator, we will do this by multiplying the entire exercise by the denominator (that is, all terms on both sides of the equation):

1x=3 1x=-3

x=3 x=-3

Answer

-3

Exercise #10

Solve for X:

x418=79 \frac{x-4}{18}=\frac{7}{9}

Video Solution

Step-by-Step Solution

To solve the equation x418=79 \frac{x-4}{18} = \frac{7}{9} , we'll follow these steps:

  • Step 1: Apply the principle of cross-multiplication to eliminate fractions.

  • Step 2: Solve for the linear expression in terms of x x .

  • Step 3: Isolate x x and solve the equation completely.

Now, let's work through each step:
Step 1: Cross-multiply to eliminate the fractions. The equation becomes:

(x4)9=1879(x4)=126 (x-4) \cdot 9 = 18 \cdot 7 \\ 9(x-4) = 126

Step 2: Distribute the 9 on the left-hand side:

9x36=126 9x - 36 = 126

Step 3: Add 36 to both sides to isolate the term with x x :

9x=126+369x=162 9x = 126 + 36 9x = 162

Step 4: Divide both sides by 9 to solve for x x :

x=1629x=18 x = \frac{162}{9} \\ x = 18

Therefore, the solution to the equation is x=18 x = 18 .

Answer

18 18

Exercise #11

Solve for X:

x+23=45 \frac{x+2}{3}=\frac{4}{5}

Video Solution

Step-by-Step Solution

To solve the equation x+23=45 \frac{x+2}{3}=\frac{4}{5} , we can follow the method of cross-multiplication:

  • Step 1: Cross-multiply to eliminate the fractions, giving us:

(x+2)5=43(x + 2) \cdot 5 = 4 \cdot 3

  • Step 2: Simplify both sides of the equation:

5(x+2)=125(x + 2) = 12

  • Step 3: Distribute the 5 on the left side:

5x+10=125x + 10 = 12

  • Step 4: Subtract 10 from both sides to isolate the term with x x :

5x=25x = 2

  • Step 5: Divide both sides by 5 to solve for x x :

x=25x = \frac{2}{5}

Therefore, the solution to the equation is 25 \frac{2}{5} .

Answer

25 \frac{2}{5}

Exercise #12

Solve for X:

78x=25 \frac{7}{8}x=\frac{2}{5}

Video Solution

Step-by-Step Solution

To solve for x x in the equation 78x=25 \frac{7}{8}x = \frac{2}{5} , we will follow these steps:

  • Multiply both sides of the equation by the reciprocal of 78\frac{7}{8}, which is 87\frac{8}{7}.
  • Simplify the resulting expression to find the value of x x .

Let's work through these steps:

First, multiply both sides by 87\frac{8}{7} to isolate x x on the left side.

87×78x=87×25 \frac{8}{7} \times \frac{7}{8}x = \frac{8}{7} \times \frac{2}{5}

This simplifies to:

x=87×25 x = \frac{8}{7} \times \frac{2}{5}

Now, perform the multiplication of the fractions:

x=8×27×5=1635 x = \frac{8 \times 2}{7 \times 5} = \frac{16}{35}

Thus, the value of x x is 1635\frac{16}{35}.

Answer

1635 \frac{16}{35}

Exercise #13

Solve for X:

22x12+1612=14.5x12 22x-\frac{1}{2}+16\frac{1}{2}=14.5x-12

Video Solution

Step-by-Step Solution

To solve the equation 22x12+1612=14.5x12 22x - \frac{1}{2} + 16\frac{1}{2} = 14.5x - 12 , we will follow these steps:
1. Combine like terms on both sides of the equation.
2. Isolate the variable x x .
3. Solve for x x .

Let's start by simplifying each side:

  • Simplify the left-hand side: 22x12+1612 22x - \frac{1}{2} + 16\frac{1}{2} .

The term 1612 16\frac{1}{2} is equivalent to 16.5 16.5 , so the left-hand side becomes:
22x0.5+16.5=22x+16 22x - 0.5 + 16.5 = 22x + 16.

  • Now simplify the right-hand side: 14.5x12 14.5x - 12 .

The right-hand side remains as 14.5x12 14.5x - 12 .

Now, let's collect like terms. Move the term involving x x from the right-hand side to the left:

  • Subtract 14.5x 14.5x from both sides:
    22x+1614.5x=12 22x + 16 - 14.5x = -12

This simplifies to:
7.5x+16=12 7.5x + 16 = -12 .

Next, isolate the constant term. Subtract 16 from both sides:

  • 7.5x+1616=1216 7.5x + 16 - 16 = -12 - 16

This simplifies to:
7.5x=28 7.5x = -28 .

Finally, solve for x x by dividing both sides by 7.5:

  • x=287.5 x = \frac{-28}{7.5}

Calculating the fraction gives approximately:
x3.73 x \approx -3.73 .

Therefore, the solution to the problem is x=3.73 x = -3.73 .

Answer

3.73 -3.73

Exercise #14

Solve for X:

18x=34 \frac{1}{8}x=\frac{3}{4}

Video Solution

Step-by-Step Solution

We use the formula:

abx=cd \frac{a}{b}x=\frac{c}{d}

x=bcad x=\frac{bc}{ad}

We multiply the numerator by X and write the exercise as follows:

x8=34 \frac{x}{8}=\frac{3}{4}

We multiply both sides by 8 to eliminate the fraction's denominator:

8×x8=34×8 8\times\frac{x}{8}=\frac{3}{4}\times8

On the left side, it seems that the 8 is reduced and the right section is multiplied:

x=244=6 x=\frac{24}{4}=6

Answer

6 6

Exercise #15

14y+12y+512=0 \frac{1}{4}y+\frac{1}{2}y+5-12=0

y=? y=\text{?}

Video Solution

Step-by-Step Solution

To solve the given linear equation, we will follow these steps:

  • Step 1: Combine the terms involving y y .
  • Step 2: Simplify the constants on the right side of the equation.
  • Step 3: Isolate y y to find its value.

Let’s solve the equation 14y+12y+512=0 \frac{1}{4}y + \frac{1}{2}y + 5 - 12 = 0 .

Step 1: Combine the like terms that involve y y .
The coefficients of y y are 14 \frac{1}{4} and 12 \frac{1}{2} . To combine them, we need a common denominator, which is 4. Therefore:

14y+12y=14y+24y=34y \frac{1}{4}y + \frac{1}{2}y = \frac{1}{4}y + \frac{2}{4}y = \frac{3}{4}y .

Step 2: Simplify the constants.
The equation now becomes 34y+512=0 \frac{3}{4}y + 5 - 12 = 0 .
Combine the constants: 512=7 5 - 12 = -7 .

The equation simplifies to 34y7=0 \frac{3}{4}y - 7 = 0 .

Step 3: Isolate y y .
Add 7 to both sides of the equation:
34y=7 \frac{3}{4}y = 7 .

To solve for y y , multiply both sides by the reciprocal of 34 \frac{3}{4} , which is 43 \frac{4}{3} :

y=7×43=283 y = 7 \times \frac{4}{3} = \frac{28}{3} .

Convert the fraction to a mixed number: 283=93+1=9 remainder 1 \frac{28}{3} = 9 \cdot 3 + 1 = 9 \text{ remainder } 1. Thus, 283=913 \frac{28}{3} = 9\frac{1}{3} .

Therefore, the value of y y is 913 9\frac{1}{3} .

Answer

913 9\frac{1}{3}

Exercise #16

5+7x2=22 \frac{-5+7x}{2}=22

How much is X worth?

Video Solution

Step-by-Step Solution

To solve this linear equation, we'll take the following steps:

  • Step 1: Multiply both sides of the equation by 2 to eliminate the fraction.
  • Step 2: Simplify and isolate the term containing x x .
  • Step 3: Solve for x x by further isolation.

Let's execute these steps:

Step 1: Start with the given equation:

5+7x2=22 \frac{-5 + 7x}{2} = 22

Multiply both sides by 2 to remove the fraction:

5+7x=44 -5 + 7x = 44

Step 2: Now, eliminate the constant term on the left side by adding 5 to both sides:

5+7x+5=44+5-5 + 7x + 5 = 44 + 5

This simplifies to:

7x=49 7x = 49

Step 3: Finally, solve for x x by dividing both sides by 7:

x=497 x = \frac{49}{7}

Calculate the result:

x=7 x = 7

Therefore, the value of x x is x=7 x = 7 .

Answer

7 7

Exercise #17

Solve for X:

17.518x5.5x=19.2+14125x 17.5-18x-5.5x=19.2+14\frac{1}{2}-5x

Video Solution

Step-by-Step Solution

To solve the equation 17.518x5.5x=19.2+14125x 17.5 - 18x - 5.5x = 19.2 + 14\frac{1}{2} - 5x , follow these steps:

Step 1: Combine like terms on both sides of the equation.

  • On the left side, combine 18x5.5x -18x - 5.5x , which simplifies to 23.5x -23.5x .
  • On the right side, simplify 19.2+14.55x 19.2 + 14.5 - 5x . The fraction 1412 14\frac{1}{2} is converted to decimal form as 14.5 14.5 , giving 19.2+14.5=33.7 19.2 + 14.5 = 33.7 .

Step 2: Rewrite the equation with the simplified terms:

17.523.5x=33.75x 17.5 - 23.5x = 33.7 - 5x .

Step 3: Get all terms involving x x on one side of the equation and constant terms on the other.

  • Add 5x 5x to both sides to move all x x related terms to the left:
  • 17.523.5x+5x=33.7 17.5 - 23.5x + 5x = 33.7
  • This further simplifies to 17.518.5x=33.7 17.5 - 18.5x = 33.7 .

    Step 4: Isolate the term with x x by subtracting 17.5 17.5 from both sides:

    18.5x=33.717.5 -18.5x = 33.7 - 17.5 .

    The right side evaluates to 16.2 16.2 .

    Thus, we have 18.5x=16.2 -18.5x = 16.2 .

    Step 5: Solve for x x by dividing both sides by 18.5-18.5:

    x=16.218.50.8757 x = \frac{16.2}{-18.5} \approx -0.8757 .

    Rounding 0.8757 -0.8757 to two decimal places gives x=0.87 x = -0.87 .

    Therefore, the solution to the equation is x=0.87 x = -0.87 .

    This corresponds to option 2 in the given choices.

Answer

0.87 -0.87

Exercise #18

Find the value of the parameter X

3x19=89 3x-\frac{1}{9}=\frac{8}{9}

Video Solution

Step-by-Step Solution

To find the value of xx in the given equation, we will perform the following steps:

  • Step 1: Start with the equation given: 3x19=893x - \frac{1}{9} = \frac{8}{9}.
  • Step 2: To eliminate the constant 19-\frac{1}{9} on the left, add 19\frac{1}{9} to both sides:

3x19+19=89+193x - \frac{1}{9} + \frac{1}{9} = \frac{8}{9} + \frac{1}{9}

This simplifies to:

3x=89+193x = \frac{8}{9} + \frac{1}{9}

Combine the fractions on the right side:

89+19=99=1\frac{8}{9} + \frac{1}{9} = \frac{9}{9} = 1

So, now we have:

3x=13x = 1

  • Step 3: Divide both sides by 3 to solve for xx:

x=13x = \frac{1}{3}

Thus, the solution to the equation is:

x=13x = \frac{1}{3}

Answer

13 \frac{1}{3}

Exercise #19

a6=67 \frac{a}{6}=\frac{6}{7}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Start with the given equation.
  • Step 2: Use cross-multiplication to eliminate the fractions.
  • Step 3: Simplify the resulting expression.
  • Step 4: Solve for the variable a a .

Now, let's work through each step:
Step 1: The equation given is a6=67 \frac{a}{6} = \frac{6}{7} .
Step 2: We apply cross-multiplication: Multiply both sides to get a×7=6×6 a \times 7 = 6 \times 6 .
Step 3: Simplify the equation: 7a=36 7a = 36 .
Step 4: Solve for a a by dividing both sides by 7:
a=367 a = \frac{36}{7} .
This fraction can be converted to a mixed number: a=517 a = 5\frac{1}{7} .

Therefore, the solution to the problem is a=517 a = 5\frac{1}{7} .

Answer

a=517 a=5\frac{1}{7}

Exercise #20

70=412b 70=4\frac{1}{2}b

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Convert the mixed number to an improper fraction
  • Step 2: Isolate b b using multiplication
  • Step 3: Simplify to find the value of b b

Now, let's work through each step:

Step 1: Convert 412 4\frac{1}{2} to an improper fraction:

412=92 4\frac{1}{2} = \frac{9}{2}

Step 2: Isolate b b on one side of the equation:

The equation becomes 70=92b 70 = \frac{9}{2}b

To isolate b b , multiply both sides by the reciprocal of 92 \frac{9}{2} :

b=70×29 b = 70 \times \frac{2}{9}

Step 3: Perform the multiplication:

b=70×29 b = \frac{70 \times 2}{9}

b=1409 b = \frac{140}{9}

The improper fraction 1409 \frac{140}{9} converts to a mixed number:

b=1559 b = 15 \frac{5}{9}

Therefore, the solution to the problem is b=1559 b = 15\frac{5}{9} .

Answer

b=1559 b=15\frac{5}{9}