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

Exercise #1

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 #2

Solve for X:

x57=211 \frac{x-5}{7}=\frac{2}{11}

Video Solution

Step-by-Step Solution

To solve x57=211 \frac{x-5}{7} = \frac{2}{11} , we will use cross-multiplication:

  • Step 1: Cross-multiply the equation: (x5)×11=7×2 (x-5) \times 11 = 7 \times 2 .
  • Step 2: Simplify both sides: 11(x5)=14 11(x - 5) = 14 .
  • Step 3: Distribute the 11 on the left side: 11x55=14 11x - 55 = 14 .
  • Step 4: Add 55 to both sides to isolate the 11x 11x term: 11x=14+55 11x = 14 + 55 .
  • Step 5: Calculate the right side: 11x=69 11x = 69 .
  • Step 6: Divide both sides by 11 to solve for x x : x=6911 x = \frac{69}{11} .

Therefore, the solution to the problem is x=6911 x = \frac{69}{11} , which matches the first answer choice provided.

Answer

6911 \frac{69}{11}

Exercise #3

Lionel buys x x packs of paper.

The price of each pack is $4.5 and he pays a total of $45.

Calculate x x .

Video Solution

Step-by-Step Solution

To solve this problem, we'll use a step-by-step approach:

Step 1: Set up the equation based on the problem statement.
The total cost Lionel pays is given by the formula:

4.5x=45 4.5x = 45

Here, x x is the number of packs Lionel buys, and $4.5 is the cost per pack.

Step 2: Solve for x x .
To find x x , divide both sides of the equation by 4.5:

x=454.5 x = \frac{45}{4.5}

Step 3: Perform the division.
Carrying out the division,

x=454.5=10 x = \frac{45}{4.5} = 10

Therefore, Lionel buys x=10 x = 10 packs of paper.

Answer

x=10 x=10

Exercise #4

1 kg of tomatoes costs $2.8.

Maggie buys 2 kg of tomatoes and 0.6 kg of cucumbers, costing a total of $7.1.

Express the value per kg of cucumbers in terms of x x (in dollars).

Video Solution

Step-by-Step Solution

To solve for the price per kg of cucumbers, follow these steps:

  • Step 1: Determine the total cost of tomatoes.
    Given that the cost of tomatoes is $2.8 per kg, and Maggie buys 2 kg, the cost of tomatoes is calculated as:
    2kg×2.8dollars/kg=5.6dollars 2 \, \text{kg} \times 2.8 \, \text{dollars/kg} = 5.6 \, \text{dollars} .

  • Step 2: Write the equation for total cost.
    The total cost for tomatoes and cucumbers combined is given as $7.1. Let x x represent the cost per kg of cucumbers. The equation representing the total cost is:
    5.6+0.6x=7.1 5.6 + 0.6x = 7.1 .

  • Step 3: Solve the equation for x x .
    Subtract the cost of tomatoes from both sides of the equation to find the cost of cucumbers:
    0.6x=7.15.6 0.6x = 7.1 - 5.6 .
    Simplifying the right side gives:
    0.6x=1.5 0.6x = 1.5 .

  • Step 4: Isolate x x by dividing both sides by 0.6:
    x=1.50.6 x = \frac{1.5}{0.6} .
    Simplify the division to find x x :
    x=2.5 x = 2.5 .

Therefore, the value per kg of cucumbers is x=2.5 x = 2.5 dollars.

Answer

x=2.5 x=2.5