Question

How do you factor $x^2-16$ completely?

Answer 1

Factor the given expression $x^2-16$ completely:

Use $a^2-b^2=\left(a+b\right)\left(a-b\right)$

Use the above algebraic identify to factor the given expression:

$\begin{array}{rcl}{x}^2-16& =& \left(x^2-4^2\right);\left[a^2-b^2=\left(a+b\right)\left(a-b\right)\right]\\ & =& \left(x+4\right)\left(x-4\right)\end{array}$

Hence, the obtained result is $\left(x+4\right)\left(x-4\right)$.