Question

Find the solution of this system of equations. Separate the x- and y-values with a comma. x - 4y = 9 and x - y = -9

Answer 1

X - 4y =  9 ------- (1)
x - y = -9 ---------(2)

(2) - (1):
-y - (-4y) = -9 - 9
-y + 4y = -18
3y = -18
y = -6 . -------- sub into (2)

x - (-6) = -9
x + 6 = -9
x = -9 - 6
x = -15

Ans: x = -15, y = -6