Find the value of x so that the function has the given value.
8. b(x) = -3x + 1; b(x) =-20
9. r (x) = 4x - 3; r (x) = 33
10. m(4) = -3/5x - 4; m(x) = 2
11. w(4) = 5/6x - 3; w(x) = -18
