Question

Using the equation y = 2x – 3, what would the input need to be for an output of 7?

Answer 1

5

Explanation:

We have an equation and are asked to find the input of x when y = 7.

The output = y = 7

The input = x

7 = 2x - 3

2x - 3 = 7

We need to find a number that multiplied by 2 which then is subtracted by 3 equals 7. We can use the backwards method to solve our answer.

2x - 3 = 7

7 + 3 = 2x

10 = 2x

Solve for x by dividing 2 from both sides :

x = 5.

Therefore, you would need an input of 5 to get 7 as the output.

Proof :

2(5) - 3 = 7

10 - 3 = 7

Answer 2

x = 5

Explanation:

Remark

This is a fancy way of asking you what is the value of x when y = 7

Equation

7 = 2x - 3

Solution

7 = 2x - 3 Add 3 to both sides

7 + 3 = 2x Combine the left.

10 = 2x Divide by 2

2x/2 = 10/2

x = 5