Chapter 8.5, Problem 8LC

To determine

To find: the factor of constant term is positive or negative of expression $x^2-x-20$ .

Answer to Problem 8LC

The sum of factors of constant term must be one positive and one negative.

Explanation of Solution

Given:

The polynomial is $x^2-x-20$ .

Calculation:

The product of first and last terms is,

  $\Rightarrow -20x^2$

Now, factor $-20x^2$ as their sum or difference that give -x as follows:

  $\begin{array}{l}-20x^2=\left(-5x\right)\left(4x\right)\\ \text{Also,}\\ 4x-5x=-x\end{array}$

Thus, the sum of factors of constant term must be one positive and one negative.