jika f (x) = ( 2x + 5 ) ^2 g(x) = -5 + 2 , a.tentukan (fog)(x) b.hitunglah (fog)(-2)

jawab

f(x)  = (2x + 5)²
g(x)= - 5x  + 2  (ini soal diubah)

a. fog(x) = f { g(x) } = f {-5x + 2 }
= { 2(-5x +2)  + 5 }²
= ( 10x + 4 + 5)²
= (10x +9)²

b. fog(-2) = f { g(-2) }
= f {-5(-2) +2 }
= f (12)
= (2.12 + 5)²
= (29)²
= 841