For the function f(x) find all values of a for which f(a) is the indicated value

For the function f(x) find all values of a for which Fla) is the indicated value 1) f(X ) = 8x - 24 f(a) = 4 2) f (x) = * F(a) = 2 3) f(x ) = 12 - 2 fla ) = 5 X 5x