GCSE Maths, Unit 7, Lesson 2 of 5

Unknowns on both sides and brackets

About 2 min to read, then 7 practice questions

Collect the x terms

Take the smaller x term away from both sides, so the x term stays positive.

  1. 7x − 4 = 3x + 16
  2. subtract 3x: 4x − 4 = 16
  3. add 4: 4x = 20
  4. x = 5

Expand first

  1. 5(x − 2) − 2(x + 3) = 2
  2. 5x − 10 − 2x − 6 = 2
  3. 3x − 16 = 2
  4. 3x = 18, so x = 6

The minus in front of the second bracket changes both signs inside it: −2 × +3 = −6.

Check with the solver

Enter 7x − 4 = 3x + 16 in the solver. Then type your own: pick any x, say 3, and make an equation with x on both sides that it solves. Does the solver agree?

Open the Equation Solver in a new tab

Practise this: 7 questions, about 11 min

Answering from memory soon after reading is what makes it stick, so now is a good time.

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