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

kf(x)

Explanation:

I got it right.

Answer 2

f(x) = ax2+bx+c, is quadratic equation
function opening downward if the a<0,
kf(x) = -x², a= -1<0
so the answer is B.kf(x)