-3 + 5a = 4a - 10
-7
-2x = x - 7 - 8
x = 5
4r + 8 + 5 = -15 - 3r
r = - 4
8x + 6x = 8x + 4x +12
x = 6
-8(n + 6) = -7(n + 7)
n = 1