(f o g)(x+1) = -2x2-4x-1 (f o g)(x) =?

misalkan a = x+1, x = a-1
(f o g)(a) = -2(a-1)²-4(a-1)-1
(f o g)(a) = -2a²+4a-2-4a+4-1
(f o g)(a) = -2a²+1
(f o g)(x) = -2x²+1