JIka f(x) = x^2+2x , g(x) = x-2 dan (fog)(p) = 0 serta (fog)(q) = -1 , makan nilai p+q adalah

(fog)(p) = [tex] (p-2)^{2} + 2(p-2) = p^{2} -4p + 4 + 2p - 4[/tex]
[tex] p^{2} - 2p = 0[/tex]
[tex]p(p-2)=0 [/tex]
[tex]p=0 \\ p=2[/tex]
[tex](fog)(q) = -1 \\ q^{2} -2q = -1 \\ q^{2} -2q + 1 + 0 \\ (q+1)(q-1)=0 \\ q=-1 \\ q=1[/tex]

(1) p + q = 0 + (-1) = -1
(2) p + q = 2 + (-1) = 1
(3) p +q = 0 + (1) = 1
(4) p + q = 2 + 1 = 3