Question

Given the following system, what is the best first step to solving by substitution? 4x-5y=-2

X=15-4y

Answer 1

4(15-4y) - 5y = -2

Explanation:

4x - 5y = -2

x = 15 - 4y:

Substitute x = 15 - 4y into the first equation:

4(15-4y) - 5y = -2

Answer 2

Substitute x into the first equation.

Explanation:

4(15-4y) - 5y = -2

The variable x is already by itself on one side of the equation. Therefore, x = 15 - 4y which means we can substitute 15 - 4y into the first equation.