# Factorising Difference of Squares: Higher Order Factorise

## Transcript

Okay! This time’s a little bit different because I’ve got power of 4. But that’s okay guys, I’m going to make it into that form, square minus the square, difference of two squares. See here guys, x4 and y4. I’m going to change that to x squared, squared. And this one is y squared, squared because remember with our indices when we did indices, hopefully, you all learned the topic of indices. We’ve had a long video on that.

Now x to the power of 4, x squared times x squared, isn’t it? So we’ve got two of a kind, so that’s why it’s x squared, squared, okay? And even when we have this, we can multiply these two together which makes four eventually. So you can separate these things like this, okay? So now we’ve got x squared, squared and y squared, squared.

So now it’s a square minus a square. So we do, x squared minus y squared, x squared plus y squared. But guys, hopefully, some of you can say don’t stop there because that’s not the end. Can you guys tell me where I should continue? Can you what about this one, can we go a little bit further on that one? That’s also a square minus a square, so that’s x squared minus y squared, so we can do this difference of two squares method once more. Can we do it for this one?

It’s a square number and a square number but we can’t apply that method to this one because it’s a plus we can only do it when it’s a negative. So this one, now we have x squared minus y squared, so we can change that to x minus y, x plus y, and then we stick that in there, x squared plus y squared. And that’s the end. So make sure you can continue when you can, okay? If any time you see a difference of two squares, always apply that method, okay?

So hopefully, that one wasn’t too difficult. Trying to remember that for me because we’re going to be using that a lot for the next parts of our algebra.