Question

When solving this system of equations, what is the first step and why?
2x + y = 15
x-y=3

Answer 1

Explanation:

Rearrange:

x-y=3

x=3+y

Substitute x as 3+y

so you can solve for y:

2(3+y)+y=15

6+3y=15

y=3

Use x=3+y to find x.