tolong dibantu ya guys makasih

1.
g(x)= 2x-4
gof(x)= 4x^2 -24x +32

gof(x)= 2(f(x)) -4
4x^2 -24x +32= 2(f(x)) -4
2(f(x)) = 4x^2 -24x+36
f(x)= 2x^2-12x+18

f(-2)= 2(-2)^2 - 12(-2) + 18= 2(4)+24+18
f(-2)= 50
jawaban: D

2.
fog(x)=x^2-4x+2
g(x)= x-3

permisalan:
a=x-3
x=a+3

f(g(x))= x^2 - 4x + 2
f(x-3)=(a+3)^2 - 4(a+3) + 2
f(a)= a^2+6a+9-4a-12+2
f(a)= a^2+2a-1
f(x)= x^2 + 2x - 1

f(-3)= (-3)^2 + 2(-3)-1=9-6-1
f(-3)= 2
jawaban: E


3.
f(x)= x+2
gof(x)= 2x^2 + 4x +1
g(2x)

permisalan:
a= x+2
x= a-2

g(f(x))= 2x^2 + 4x +1
g(x+2)= 2(a-2)^2 + 4(a-2) + 1
g(a)= 2a^2 - 8a + 8 + 4a - 8 +1
g(a) = 2a^2 - 4a + 1

g(2x)= 2(2x)^2 - 4(2x) + 1
g(2x)= 8x^2-8x+1

jawaban: C..