# How do you factor #25x^2-81#?

##### 2 Answers

The answer is:

You first move the

We then get the square root of both sides of the equation.

The square roots are:

Applying this to our equation makes it like this.

We divide both sides by 5

This cancels both 5 on the

And we reach our answer:

When you see the numbers 25 and 81, you should realise that we will most probably be using the **Sum or Difference of Squares Identities.**

As there is a negative sign, we will use the **Difference of Squares Identity**

It says

We can write the expression as