This study notes covers Worked Example 3: Subject Appears Twice (Higher) within Rearranging Formulae for GCSE Mathematics. Revise Rearranging Formulae in Algebra for GCSE Mathematics with 14 exam-style questions and 11 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 5 of 6 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Worked Example 3: Subject Appears Twice (Higher)
Make x the subject of: 3x + 5 = 2(x + y)
Step 1 Expand and collect x terms
3x + 5 = 2x + 2y
3x − 2x = 2y − 5
x = 2y − 5
Practice questions for Rearranging Formulae
Make b the subject of the formula: a = b + c
The circumference of a circle is given by the formula: C = 2πr Make r the subject of the formula.
Quick recall flashcards
What is the 'subject' of a formula?
The variable that stands alone on one side of the equals sign. In v = u + at, v is the subject.
What does 'rearranging a formula' produce?
An equivalent formula expressing a different variable as the subject. E.g. v = u + at rearranges to a = (v − u)/t.