tolong no 11 12 13 + cara penyelesaiannya, tolongg

no. 12
g(f(x)) = 8x^2+2x+1
g(2x+1) = 8x^2+2x+1
misalkan y = 2x+1 shngga x = (y-1)/2
g(y) = 8((y-1)/2)^2 + 2((y-1)/2) + 1
g(y) = 2y^2-3y+2
jadi g(x) = 2x^2-3x+2 (D)

no. 13
f(x) = (2x+1)/x
misalkan f(x) = y maka
y = (2x+1)/x
xy = 2x+1
xy - 2x = 1
x(y-2) = 1
x = 1/(y-2)
f^-1 (x) = 1/(x-2)

(f^-1 o g)(x) = 1/((x+3)-2) = 1/(x+1)
(f^-1 o g)(3) = 1/(3+1) = 1/4 (C)