# Lesson video

In progress...

Hi, I'm Miss Davis.

In this lesson, we're going to be changing the subject of a formula where the wanted subject appears twice.

We've been asked to make y the subject, this means we need to write this equation as y equals something.

Let's start by subtracting ny from both sides.

This means that we've collected our y terms on the same side of the equal symbol.

Next, we're going to subtract t from both sides so that we are only left with y terms on that left hand side.

Next, we're going to factorise the left hand side of the equation taking y out as a factor, we can then divide both sides by m subtract n to leave y on its own.

This gives y is equal to c, subtract t divided by m subtract n.

Here are some questions for you to try.

Pause the video to complete your task and resume once you're finished.

Here are the answers, make sure that if the formula has brackets in it, you are expanding these out first.

If it doesn't, you need to collect the Xs in this case, on one side first.

Here are some questions for you to try.

Pause the video to complete your task and resume once you are finished.

Here are the answers.

Make sure that you're expanding any brackets first, and then collecting the Xs, in this case, on the same size of the equal symbol.

That's all for this lesson.

Thanks for watching.