need help with zeros of polynomial?

Question

f(x)=(x-4)(x+2)(x-1)

also is (x-3) a factor of
p(x)=x^4-5x^2-27x+15

Answer 1

For the first question, set each factor to zero and solve.
The zeros are 4, -2 and 1.
For the second question:
The answer is "no".
x-3 is a factor of p(x) if and only if p(3) = 0.
But p(3) = 81-45-81 + 15 = -30.

Answer 2

4,1,-2