Question

How do you factor `4-81w^2`?

Answer 1

`4-81w^2=(2+9w)(2-9w)`

Explanation:

We use the identity `a^2-b^2=(a+b)(a-b)`

Hence `4-81w^2`

= `2^2-(9w)^2`

= `(2+9w)(2-9w)`