Given that the polynomial is degree 4, without loss of generality we can assume that it is monic, as the leading coefficient has no bearing on the roots of P(x):
a) P(x) = (x-2)(x+2)(x^2 +bx + c) [Since we know that the polynomial is degree 4]
b) Now P(0) = (0-2)(0+2)(0^2 + b(0) + c) = 4...