Question

1. f(x)= -2x²+6x-3
g(x)= -3x+7
2.f(x)= -x²-11x+7
g(x)=2x+3
Tentukan:
f o g(x) & g o f(x)

Answer 1

1. f ○ g(x) = f(g(x))
f(-3x + 7) = -2(-3x+7)^2 + 6(-3x+7) - 3
= -2(9x^2-42x+49) - 18x+42 - 3
= -18x^2+84x-98 -18x+39
= -18x^2 + 66x - 59
g ○ f(x) = g(f(x))
g(-2x^2+6x-3) = -3(-2x^2+6x-3) + 7
= 6x^2 - 18 x + 16

2. f ○ g(x) = f(g(x))
f(2x+3) = -(2x+3)^2 - 11(2x+3) + 7
= -(4x^2+12x+9) - 22x - 33 + 7
= -4x^2 - 34x - 35
g ○ f(x) = g(f(x))
g(-x^2-11x+7) = 2(-x^2-11x+7) + 3
= -2x^2 - 22x + 17