Answer: D
Step-by-step explanation:
Yeah, lets look at each of the functions. I'll refer to them as A, B, C, D, and E.
A) f(x)=x^2-16
This has two zero. x^2-16= (x+4)(x-4), which two zeroes include -4 and 4.
Here we introduce an important concept, if the function isn't a perfect square, and is a quadratic, it has two zeroes.
B) This is linear, so it obviously has 1 zero.
C) Two zeroes, because it isn't a perfect square.
D) x^2-10x+25 = (x-5)^2, so it has only one zero.
E) Not a perfect square, so two roots.
