Question

Which of these is the composite function f(g(x))?

f(x) = x2 – 5
g(x) = 9x – 2

A. f(g(x)) = 9x2 – 1
B. f(g(x)) = 9x2 – 9
C. f(g(x)) = 81x2 – 18x – 9
D. f(g(x)) = 81x2 – 36x – 1

Answer 1

( 9x – 2 )2 – 5

plug in all the 9x – 2 into all the xs in the x2-5 function

Answer 2

and of course

( 9x – 2 )2 – 5 is actually

( 9x – 2 )*( 9x – 2 ) -5

foil out ^^^ -5

Answer 3

Since this is just f(g(x)) we would take g(x) and plug in it for 'x' anywhere we see it in f(x)

since f(x) = x² - 5...we replace 'x' with 9x - 2

(9x - 2)² - 5

And now simplify

Answer 4

81x^2-36x-1?

Answer 5

That would be correct!

Answer 6

Sweet. Your awesome! Thank you both Tim and John!

Answer 7

No problem :)