ketahui fungsi komposisi

f(x + 1) = 2x² - 4x - 5
misal :
x + 1 = a
x = a - 1

f(a) = 2(a - 1)² - 4(a - 1) - 5
f(a) = 2a² - 8a + 1
f(x) = 2x² - 8x + 1

g(x) = 3x - 1

(gof)(x)
= 3(2x² - 8x + 1) - 1
= 6x² - 24x + 2

jawab

f(x +1) = 2x² - 4x - 5
f(x) =2(x-1)² - 4(x -1) - 5
f(x) = 2(x² - 2x +1) - 4x + 4 - 5
f(x) = 2x² - 4x + 2 -4x + 4 - 5
f(x) = 2x² - 8x  +1

g(x) = 3x -1

gof(x) = g {f(x)}
= g{2x²-8x + 1}
= 3(2x² -8x + 1) -1 
= 6x² - 24x + 2