Question

Facot the expression 81x^2-25 ?

Answer 1

`81x^2\text{ - 25}`

Apply difference of two square

`x^2-y^2\text{ = (x - y)(x + y)}`

`\begin{gathered} 81x^2\text{ - 25} \\ =(9x)^2-5^2 \\ \text{Apply difference of two square} \\ =\text{ (9x - 5)(9x + 5)} \end{gathered}`