 This video, we're going to look at how to expand double brackets. You should already know how to expand single brackets, but if you've forgotten, you may want to watch this video first. Once we know how to expand double brackets, we'll also be able to expand triple brackets and so on. So we'll have a look at a triple brackets example towards the end of this video. Let's get started with the double brackets. Remember that in algebra, when two things are next to each other, it means they are multiplied. So we need to multiply everything in the second bracket, but everything in the first bracket. I'm going to show you two methods, and then you choose whichever one you prefer. For the first method, we draw arcs linking each term. So x multiplied by x is x squared, x multiplied by 3 is 3x, negative 5 multiplied by x is negative 5x, and negative 5 multiplied by positive 3 is negative 15. See how I've ended up with four arcs. That's really important because it means I haven't missed anything out. Some people like to remember this as foil, first, outer, inner, last. The second method is by splitting up each bracket into a grid. And then just multiply each bit together, x multiplied by x gives x squared, x times negative 5 is negative 5x, 3 times x is 3x, and 3 times negative 5 is negative 15. For both methods, we then just need to simplify the middle terms by adding 3x and negative 5x to get negative 2x. So that's our final answer. So here's one for you to do. Pause the video, expand the brackets and simplify the answer. Click play when you're ready. Did you get it right? There are two more questions for you to do before we look at triple brackets. Pause the video, expand and simplify and click play when you're ready. How did you get on? For the final answer, it doesn't matter which order you write the terms in. This could also have been written like this. So let's end with triple brackets. They follow the exact same process as double brackets. Start by expanding the first two brackets like you would normally. x squared plus 3x minus 5x minus 15. And simplify it. Now multiply this by the third bracket. Make sure you simplify to get the final answer. Give this triple bracket a go. Pause the video, work out the answer and click play when you're ready. Did you get it right? So there we have expanding double brackets and even triple brackets. We just need to remember to multiply everything in the second bracket by everything in the first bracket so that we end up with four terms. And then we simplify it. In this video I showed you two different methods so you choose which one you prefer.