Tolong bantuannya untuk nomor 4 dan 5 beserta caranya. Terimakasih

4) (f o g)(x) = 4x^2 + 8x - 3
f(g(x)) = 4x^2 + 8x - 3
f(2x + 4) = 4x^2 + 8x - 3
Misal 2x + 4 = a => 2x = a - 4 => x = (a - 4)/2
f(a) = 4((a - 4)/2)^2 + 8(a - 4)/2 - 3
f(a) = 4(a^2 - 8a + 16)/4 + 4(a - 4) - 3
f(a) = a^2 - 8a + 16 + 4a - 16 - 3
f(a) = a^2 - 4a - 3
f(x) = x^2 - 4x - 3
x^2 - 4x - 3 = y
x^2 - 4x = y + 3
x^2 - 4x + ... = y + 3 + ...
x^2 - 4x + 4 = y + 3 + 4
(x - 2)^2 = y + 7
x - 2 = √(y + 7)
x = 2 + √(y + 7)
f^-1(x) = 2 + √(x + 7)

5) (g o f)(x) = (f o g)(x)
g(f(x)) = f(g(x))
3f(x) + 50 = 2g(x) + c
3(2x + c) + 50 = 2(3x + 50) + c
6x + 3c + 50 = 6x + 100 + c
2c = 50
C = 25