Solving a system of equations problem

Question

4x-8y=20

-2x+4y=-10

Answer 1

4x-8y=20

-2x+4y=-10

multiply the second equation by -2

-2(-2x)+(-2)(4y)=-2(-10)

4x-8y=20

the equations are the same; one line is on top of the other

any solution to one equation is a solution to the other