Diketahui sistem persamaan linear dua fariabel: x+y = -5 x -2y =4. Maka nilai 2x -4y adalah

jwab

x + y = - 5
x - 2y = 4
................(-)
3y = - 9
y = - 3

x = - 5 - y
x = -5 - (-3)
x = - 5 +3
x = -2

nilai 2x - 4y = 2(-2) - 4(-3) = - 4 + 12 = 8