carilah x dan y dari persamaan bentuk menggunakan substitusi -2x + 4y = -20 dan 4x+2y = 30

-2x + 4y = -20 (×2)
4x + 2y = 30 (×1)

-4x + 8y = -40
4x + 2y = 30
——————— +
10y = -10
y = -1

4x + 2y = 30
4x + 2(-1) = 30
4x -2 = 30
4x = 32
x = 8

-2x + 4y = -20
4y = -20 + 2x
2y = -10 + x

4x + 2y = 30
4x + (-10 + x) = 30
4x -10 + x = 30
5x = 40
x = 8
---------------------------------
-2x + 4y = -20
4y + 20 = 2x
8y + 40 = 4x

4x + 2y = 30
8y + 40 + 2y = 30
10y = -10
y = -1