Answer:
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
