Chapter 14.8, Problem 8PPS

To determine

To calculate: The factors of the trinomial $m^2-4m-21$ .

Answer to Problem 8PPS

The factors of the trinomial $m^2-4m-21$ are $m-7\text{and}m+3$ .

Explanation of Solution

Given Information:

The trinomial expression is $m^2-4m-21$ .

Calculation:

The given trinomial is $m^2-4m-21$ .

Split $-4m$ into two parts such that their product is equal to the product of $m^2$ and $-21$ .

  $\begin{array}{c}{m}^2-4m-21=m^2-7m+3m-21\\ =m\left(m-7\right)+3\left(m-7\right)\\ =\left(m+3\right)\left(m-7\right)\end{array}$

Hence, the factors of the trinomial $m^2-4m-21$ are $m-7\text{and}m+3$ .