Question

Given the function f(x) = x2 and k = –1, which of the following represents a function opening downward?

A. f(x) + k
B. kf(x)
C. f(x + k)
D. f(kx)

Answer 1

I just got it wrong. The right answer is: kf(x)

Explanation:

Answer 2

to reflect the function across the x axis, we must multiply the whole thing by -1
f(kx) is the answer to make the thing negative
so you should result with
f(x)=-x^2
basically the answer is D