tolong jawab plis makasih

1.
f(x) = a + 2x
g(x) = bx - 6
f(0) = g(3) = 9

#mncari nilai a dan b
f(0) = 9
a + 2(0) = 9
a = 9

g(3) = 9
bx - 6 = 9
3b = 9+6
b = 15/3
b= 5

=>>subsitusi nilai a dan b ke pers. f(x) dan g(x)

f(x) = 2x + 9 ,,, g(x) = 5x - 6

#(g○f)(x) = 5 (2x + 9) - 6
= 10x + 45 - 6
= 10x + 39
(g○f)(-3) = 10 (-3) + 39
= -30 + 39 = 9

#g(x) invers
[tex] {g}^{ - 1} (x) = 5x - 6 \\ y = 5x - 6 \\ 5x = y + 6 \\ x = \frac{y + 6}{5} \\ {g}^{ - 1} (x) = \frac{x + 6}{5} \\ \\ jadi \\ {g}^{ - 1} (4) = \frac{4 + 6}{5} = \frac{10}{5} = 2[/tex]