Jawabanmu

2014-02-25T15:44:03+07:00
(fog)(x)=  x^{2} + 2x +1
 (x-1)^{2} + 2(x - 1) + 1
=x² -2x +1 + 2x - 2 +1
=x²
(fog)(4) = (4)²
= 16