Lesson video

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 in an algebraic fraction.

We have been asked to make y the subject, y appears in the numerator and the denominator of this algebraic fraction.

Let's start by multiplying both sides of this equation by n, y add C.

We can then expand the bracket on the left-hand side.

This gives us t and y, add c, t is equal to m, y.

We need to group our y turns on the same side of the equal symbol.

To do this, we're going to subtract t and y from both sides, we can then take y out as a factor on the right-hand side.

To be left with y on its own as the subject, we're going to divide both sides by m subtract t, n, this leaves us with just y on that right-hand side and is equal to c, t divided by m subtract t, 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 you're multiplying by the denominator and then collecting the xs on the same side.

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.

This can't be the correct answer because x appears on both sides of the equal symbol.

Jesse should have collected the xs on the same side, and then factorised to give the correct answer of x equals t add five divided by a add four.

That's all for this lesson, thanks for watching.