f(x)= x2-4x+6 g(x)= 3x-5 jika (gof)(x) = 13, tentukan x

(gof)(x): (g(fog))(x)
(13)(x): ( 3x(4x+6)-5)
13(x) :12x"+18x-5
(x) 12x"+18x-5-13
12x"+18x-18

f(x)= x²-4x+6          g(x)= 3x-5
(gof)(x) = 13
g(f(x)) = 13
g(x²-4x+6) = 13
3(x²-4x+6)-5 = 13
3(x²-4x+6) = 13+5
3(x²-4x+6) = 18
(x²-4x+6) = 6
x²-4x+6-6 = 0
x²-4x = 0
x(x-4) = 0
x = 0 atau x-4 = 0
                 x =4