Algebra and proofAdditional / Further Maths

Rearranging a formula - one occurrence

Isolate the requested variable using inverse operations.

  • Treat the other letters as numbers that are not yet specified.
  • Undo operations in reverse order and keep both sides balanced.
  • Use brackets to preserve an entire numerator.

Example 1

Undo a multiplier

Make the stated variable the subject of the formula.

Apply this to both sides.Apply this to both sides; then write the subject on the left.

Example 2

Clear a denominator

Rearrange the formula for the stated variable.

Apply this to both sides.Collect the terms to obtain , then divide both sides by .

Remember
Any expression you divide by must be non-zero.

Your turn

Question 1

Make the subject.

Check answer
Collect the terms to obtain , then divide both sides by .
Question 2

Make the subject.

Check answer
Collect the terms to obtain , then divide both sides by .
Question 3

Make the subject.

Check answer
Require , then write on the left.
Question 4

Make the subject.

Check answer
Collect the terms to obtain , then divide both sides by .
Question 5

Make the subject.

Check answer
Collect the terms to obtain , then divide both sides by .
← All Algebra and proof cardsReport a mistake