Algebra practice problems GCSE Maths, Topic 2
Solving equations, sequences and the nth term, factorising, simultaneous equations, straight-line graphs and quadratics. Try each question before you look: use the hint if you are stuck, then reveal the worked solution one step at a time.
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Key equations for algebra
| y = mx + c | straight line: gradient m, y-intercept c |
|---|---|
| m = (y2 − y1)/(x2 − x1) | gradient between two points |
| x = (−b ± √(b2 − 4ac))/(2a) | quadratic formula (on the formulae sheet) |
A formulae sheet is provided in the 2025, 2026 and 2027 GCSE Maths exams. Answers within 2.5% are marked correct, and you can type fractions such as 23/20. Every topic, Foundation and Higher, is in our GCSE Maths topic list.
Warm-up questions
Quick checks on the core ideas. If these feel easy, go straight to the exam-style questions.
Hint
Subtract 7 from both sides, then divide by 3.
Worked solution
- 3x = 15.
- x = 5.
Hint
Substitute n = 10.
Worked solution
- 4 × 10 − 1 = 39.
Hint
Find two numbers that multiply to 6 and add to 5.
Worked solution
- 2 × 3 = 6 and 2 + 3 = 5.
- So x2 + 5x + 6 = (x + 2)(x + 3): B.
Exam-style questions
Questions at the level of the GCSE Maths exam. The ones marked Challenge combine more than one idea.
Hint
Expand the bracket first.
Worked solution
- 5x − 10 = 2x + 11.
- 3x = 21.
- x = 7.
Hint
Add the equations to eliminate y.
Worked solution
- Adding: 3x = 12, so x = 4.
- Then y = 3. So x = 4.
Hint
Change in y divided by change in x.
Worked solution
- (12 − 3)/(4 − 1) = 9/3.
- Gradient = 3.
Hint
It does not factorise. Use the quadratic formula with a = 1, b = −4, c = −7.
Worked solution
- x = (4 ± √(16 + 28))/2 = (4 ± √44)/2.
- x = (4 + 6.633)/2 = 5.32 (the other solution is −1.32).
Hint
Multiply every term by 6 to clear the fractions.
Worked solution
- 3(x + 3) + 2(x − 1) = 24.
- 3x + 9 + 2x − 2 = 24, so 5x = 17.
- x = 3.4.
Exam question practice
One original exam-style question in the style of a GCSE paper. Answer it in full, with working, before you open the mark scheme: most marks are for method, so show every step.
Exam-style question style · 5 points · about 6 minutes
A rectangle has length (2x − 1) cm and width (x + 3) cm. Its perimeter is 34 cm.
- (a) Show that 6x + 4 = 34.
- (b) Solve the equation to find x.
- (c) Work out the area of the rectangle.
Write your full answer on paper first, then open the scoring guide and tick each point you earned.
Scoring guide and model answer
Part (a)
Perimeter = 2(2x − 1) + 2(x + 3) = 4x − 2 + 2x + 6 = 6x + 4, so 6x + 4 = 34.
Part (b)
6x = 30, so x = 5.
Part (c)
Length 2(5) − 1 = 9 cm, width 5 + 3 = 8 cm. Area = 72 cm2.
Your mark: 0 of 5
Common mistakes in algebra
- Multiplying only the first term when expanding a bracket.
- Sign errors when moving terms across the equals sign.
- Getting the gradient upside down: it is change in y over change in x.
- Giving only one solution of a quadratic when there are two.
Keep going
Revise the ideas behind these questions:
- Simultaneous equations guide
- Factorising quadratics guide
- Quadratic formula guide
- nth term guide
- Straight-line graphs guide
Then try real exam questions: GCSE Maths past papers, with official scoring guidelines. · All GCSE Maths units