Collect every term with the new subject on one side, factorise it out, then divide.
What you will learn
- Clear fractions and expand brackets first
- Collect the subject terms and factorise
- Rearrange formulae like y = (x + 2)/(x − 3)
Collect, factorise, divide
When the subject appears twice, you cannot just undo the operations.
Get every term with it on one side, the rest on the other, then factorise.
- make x the subject of y(x + 2) = 3x − 1
- xy + 2y = 3x − 1
- 2y + 1 = 3x − xy
- 2y + 1 = x(3 − y)
- x = (2y + 1)/(3 − y)
The rest of this lesson and its 7 practice questions are locked.
In this lesson
- Collect, factorise, divide
- With a fraction
7 practice questions, marked as you go; about 25 minutes in all.
In this unit: Formulae and rearranging
Substitute into formulae, write your own, change the subject (including when it appears twice) and use rearranged formulae from science and finance.
- Substituting into formulae
- Writing formulae
- Changing the subject
- When the subject appears twice
- Using formulae