Examples with solutions for Solving an Equation by Multiplication/ Division: Using order of arithmetic operations

Exercise #1

92x×224 ⁣:4=64 92-x\times2-24\colon4=64

Calculate X.

Video Solution

Step-by-Step Solution

First, we solve the multiplication and division exercises, we will put them in parentheses to avoid confusion:

92(x×2)(24 ⁣:4)=64 92-(x\times2)-(24\colon4)=64

922x6=64 92-2x-6=64

Reduce:

862x=64 86-2x=64

Move the sides:

2x=6486 -2x=64-86

2x=22 -2x=-22

Divide by negative 2:

x=222 x=\frac{-22}{-2}

x=11 x=11

Answer

11

Exercise #2

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 #3

5x43+4x+3x=0 5x-4\cdot3+4x+3x=0

Video Solution

Step-by-Step Solution

To solve this linear equation 5x43+4x+3x=0 5x - 4 \cdot 3 + 4x + 3x = 0 , follow these steps:

  • Simplify the expression: First, calculate the product 43 4 \cdot 3 . This equals 12 12 .

  • Substitute back into the equation: 5x12+4x+3x=0 5x - 12 + 4x + 3x = 0 .

  • Combine like terms:

    • The terms involving x x are 5x 5x , 4x 4x , and 3x 3x . Add these together: 5x+4x+3x=12x 5x + 4x + 3x = 12x .

  • The equation now simplifies to 12x12=0 12x - 12 = 0 .

  • Isolate x x : Add 12 12 to both sides of the equation to eliminate the constant term on the left:

    • 12x12+12=0+12 12x - 12 + 12 = 0 + 12 , which simplifies to 12x=12 12x = 12 .

  • Solve for x x : Divide both sides by 12 12 to solve for x x :

    • x=1212=1 x = \frac{12}{12} = 1 .

The solution to the equation is x=1 x = 1 .

Verify with the given choices, we find that the correct answer is: x=1 x = 1 .

Answer

x=1 x=1

Exercise #4

2x41+x+2=19 2x\cdot4-1+x+2=19

Video Solution

Step-by-Step Solution

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

  • Step 1: Eliminate multiplication by distributing 2x4 2x \cdot 4 .
  • Step 2: Combine like terms on the left side of the equation.
  • Step 3: Isolate the variable x x by moving constants to the opposite side.

Let's work through these steps:

Step 1: The given equation is 2x41+x+2=19 2x \cdot 4 - 1 + x + 2 = 19 .
Distribute the multiplication on 2x4 2x \cdot 4 to get 8x 8x :

8x1+x+2=19 8x - 1 + x + 2 = 19

Step 2: Combine the like terms (8x 8x and x x ):

9x1+2=19 9x - 1 + 2 = 19

Simplify further by combining constants 1+2-1 + 2 to get:

9x+1=19 9x + 1 = 19

Step 3: Isolate x x by subtracting 1 from both sides:

9x=18 9x = 18

Finally, divide both sides by 9 to solve for x x :

x=189=2 x = \frac{18}{9} = 2

Therefore, the solution to the problem is x=2 x = 2 .

Answer

x=2 x=2

Exercise #5

5+4x23+2x3=9 5+4x-2\cdot3+2x\cdot3=9

Video Solution

Step-by-Step Solution

To solve this problem, we'll proceed with these steps:

  • Simplify the equation by performing arithmetic operations.
  • Combine like terms.
  • Solve the resulting equation for the variable x x .

Now, let's work through these steps:

Simplify the equation given by performing the multiplication and subtraction:

5+4x23+2x3=9 5 + 4x - 2 \cdot 3 + 2x \cdot 3 = 9 
5+4x6+6x=9 5 + 4x - 6 + 6x = 9 

Combine like terms on the left side:

(56)+4x+6x=9 (5 - 6) + 4x + 6x = 9 
1+10x=9 -1 + 10x = 9 

To isolate 10x 10x , add 1 to both sides of the equation:

10x=9+1 10x = 9 + 1 
10x=10 10x = 10 

Divide both sides by 10 to solve for x x :

x=1010 x = \frac{10}{10} 
x=1 x = 1 

Therefore, the solution to the equation is x=1 x = 1 .

Comparing this with the provided answer choices, we see that the correct choice is:

x=1 x=1

Answer

x=1 x=1

Exercise #6

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 #7

2y1yy+4=8y 2y\cdot\frac{1}{y}-y+4=8y

y=? y=\text{?}

Video Solution

Step-by-Step Solution

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

  • Simplify the term 2y1y 2y \cdot \frac{1}{y}
  • Rearrange the equation to group similar terms
  • Solve for y y

Now, let's work through each step:

Step 1: Simplify the expression 2y1y 2y \cdot \frac{1}{y} .

The term 2y1y 2y \cdot \frac{1}{y} simplifies directly to 2 2 since y y in the numerator and denominator cancel each other out assuming y0 y \neq 0 . Therefore, the equation becomes:

2y+4=8y 2 - y + 4 = 8y

Step 2: Combine like terms on the left-hand side:

2+4=6 2 + 4 = 6 , so the equation now is 6y=8y 6 - y = 8y .

Step 3: Rearrange the equation to isolate y y on one side. Add y y to both sides to get rid of the negative y y :

6=8y+y 6 = 8y + y

This simplifies to:

6=9y 6 = 9y

Step 4: Solve for y y by dividing both sides by 9:

y=69 y = \frac{6}{9}

Simplify the fraction to get:

y=23 y = \frac{2}{3}

Therefore, the solution to the problem is 23 \frac{2}{3} .

Answer

23 \frac{2}{3}

Exercise #8

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 #9

6x24+2x+2=5 6x\cdot2-4+2x+2=5

Video Solution

Step-by-Step Solution

To solve the linear equation 6x24+2x+2=5 6x \cdot 2 - 4 + 2x + 2 = 5 , follow these steps:

  • Step 1: Simplify the expression on the left-hand side of the equation.
  • Step 2: Combine like terms to reduce the equation.
  • Step 3: Isolate the variable x x to determine its value.

Let's simplify and solve the given equation:

Step 1: Simplify the expression 6x24+2x+2 6x \cdot 2 - 4 + 2x + 2 .
This becomes 12x4+2x+2 12x - 4 + 2x + 2 .

Step 2: Combine like terms.
Combine the terms involving x x : 12x+2x=14x 12x + 2x = 14x .
Combine the constants: 4+2=2-4 + 2 = -2.
This results in the equation 14x2=5 14x - 2 = 5 .

Step 3: Isolate x x .
Add 2 to both sides to eliminate the constant on the left:
14x2+2=5+2 14x - 2 + 2 = 5 + 2 .
This simplifies to 14x=7 14x = 7 .
Next, divide both sides by 14 to solve for x x :
x=714 x = \frac{7}{14} .

Simplify the fraction:x=12 x = \frac{1}{2} .

Therefore, the solution to the equation is x=12 x = \frac{1}{2} .

Answer

x=12 x=\frac{1}{2}

Exercise #10

Solve for X:

x+43=78 \frac{x+4}{3}=\frac{7}{8}

Video Solution

Step-by-Step Solution

First, we cross multiply:

8×(x+4)=3×7 8\times(x+4)=3\times7

We multiply the right section and expand the parenthesis, multiplying each of the terms by 8:

8x+32=21 8x+32=21

We rearrange the equation remembering change the plus and minus signs accordingly:

8x=2132 8x=21-32
Solve the subtraction exercise on the right side and divide by 8:

8x=11 8x=-11

8x8=118 \frac{8x}{8}=-\frac{11}{8}

Convert the simple fraction into a mixed fraction:

x=138 x=-1\frac{3}{8}

Answer

138 -1\frac{3}{8}