Lemmara logoLemmaraWorked solution

4MA1/1F Jan 2021, Question 12: Substitution

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 1F (Foundation) · Calculator · 5 marks

اقرأ هذا الحل مشروحاً بالعربي ←

The question, in short

Expand a product, evaluate t = ab − c with a = 1.5, b = 2.4, c = −5.6, and rearrange y = dx − e to make d the subject.

Summarised in our own words. Use the official paper for the exact wording and any diagrams.

Part (a) · 1 mark

Expand x(4 − x).

  1. 1x(4 − x) = 4x − x²

Answer4x − x²

Part (b) · 2 marks

Calculate t = ab − c using a = 1.5, b = 2.4 and c = −5.6.

  1. 11.5 × 2.4 = 3.6
  2. 23.6 − (−5.6) = 3.6 + 5.6
  3. 33.6 + 5.6 = 9.2

Answer9.2

Part (c) · 2 marks

Rearrange y = dx − e so that d is the subject.

  1. 1y = dx − e
  2. 2y + e = dx
  3. 3(y + e)/x = d
  4. 4d = (y + e)/x

Answerd = (y + e)/x

Stuck on a step? Read the free lesson: Substitution

Practise more substitution questions

Real 4MA1 past-paper questions, marked on your working like the exam, with a worked solution for every part.

Practise free on Lemmara

More past-paper questions on substitution

Also searched as: 4MA1 1F January 2021 · 4MA1/1F · 4ma1 jan21 1f · question 12.
Lemmara is an independent study tool, not affiliated with or endorsed by Pearson Edexcel. The worked solutions are Lemmara’s own.