diketahui s×+2y=-3 dan 7×+8y=1 nilai x-y adalah a.-2 b.-1 c.0 d.1

5x+2y = -3
7x+8y = 1
________
20x+8y = -12
7x+8y = 1
________—
13x = -13
x = -1

7(-1)+8y = 1
8y = 8
y = 1

Maka, x-y = -1-1 = -2