diketahui f(x)=(2x-5)² dan g(x)=7-x tentukan (fog)(x)

f(x) = (2x - 5)²
f(x) = 4x² - 10x + 25
g(x) = 7 - x

maka :
f o g (x) = f(g(x)) = f(7 - x)

=> f o g (x) = 4(7-x)² - 10(7-x) + 25
=> f o g (x) = 4(49 - 14x + x²) - 70 + 10x + 25
=> f o g (x) = 196 - 56x + 4x² - 45 + 10x
=> f o g (x) = 4x² - 46x + 151