When expressions of the form \((x-r)(x-s)\) are multiplied out, a quadratic
polynomial is obtained. For instance, \((x-2)(x-(-7))=(x-2)(x+7)=x^{2}+5 x-14
.\)
\(H\) a. What can be said about the coefficients of the polynomial obtained by
multiplying out \((x-r)(x-s)\) when both \(r\) and \(s\) are odd integers? when both
\(r\) and \(s\) are even integers? when one of \(r\) and \(s\) is even and the other
is odd?
b. It follows from part (a) that \(x^{3}-1253 x+255\) cannot be written as a
product of two polynomials with integer coefficients. Explain why this is so.