Use the function to answer the question.

f (x) = 4x - 1; g (x) = 5x^2

What is equal to (f o g) (x) ?

80x^2 - 40x + 5

20x^3 - 5x^2

5x^2 + 4x - 1

20x^2 - 1

20x^2 - 1 (fourth possible answer is the correct one)

Step-by-step explanation:

To obtain (f o g) (x), use function g (x) as the input (x) to f (x), as follows:

f (x) = 4x - 1 becomes f (g (x)) = 4g (x) - 1.

But g (x) = 5x^2, so we get:

f (g (x)) = 4 (5x^2) - 1

and this simplifies to: f (g (x)) = 20x^2 - 1