Question

What is the solution to this system of equations?

x − 2y = 15
2x + 4y = -18

Please explain! the sooner the better

Answer 1

2( 2y + 15) + 4 y = +18
4y + 30 + 4 y = -18
8y + 30 = -18
8y = -18 -30
8y = -48
y = -6

x +12 = 15
x = 15 - 12
x = 3
Final answer= (3, -6)

Answer 2

first for the first equation x = 2y +15
Substitute x in the second equation
2( 2y + 15) + 4 y = +18
4y + 30 + 4 y = -18
8y + 30 = -18
8y = -18 -30
8y = -48
y = -6

Substitute in first equation x -2(-6) = 15
x +12 = 15
x = 15 - 12
x = 3
so the solution is (3, -6)