Question

Factor this polynomial completelyx2 - 81

Answer 1

We want to factor the polynomial

`x^2-81`

This means we are to factorise it. This becomes

`\begin{gathered} x^2-81 \\ x(x)-9(9) \\ \text{collecting the terms outside the bracket } \\ (x-9) \\ \text{and the terms in bracket} \\ (x+9) \\ so\text{ we have } \\ (x-9)(x+9) \end{gathered}`

Hence, the answer is

`(x-9)(x+9)`