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4024/22 May/Jun 2022, Question 2: Substitution

Cambridge O Level Mathematics 4024 · Paper 22 (Calculator) · Calculator · 9 marks

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The question, in short

Five short algebra tasks: substitute values into a formula, expand and simplify brackets, solve a linear equation, factorise an expression, and change the subject of a formula.

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

Part (a) · 2 marks

Given A = 3p + q, work out the value of q using A = 23 and p = 5.

  1. 123 = 3 × 5 + q
  2. 2q = 23 − 15 = 8

Answer8

Part (b) · 2 marks

Multiply out the brackets in 2(2x + 5) + 3(x − 6) and collect like terms.

  1. 14x + 10 + 3x − 18
  2. 2= 7x − 8

Answer7x − 8

Part (c) · 2 marks

Find the value of y that satisfies 5y + 3 = 1.

  1. 15y = 1 − 3 = −2
  2. 2y = −2/5 = −0.4

Answer−0.4 or −2/5

Part (d) · 2 marks

Write 12r² − 8rs as a product of factors.

  1. 1Common factor 4r
  2. 212r² − 8rs = 4r(3r − 2s)

Answer4r(3r − 2s)

Part (e) · 1 mark

Rewrite a = 3b so that b is expressed in terms of a.

  1. 1b = a/3

Answerb = a/3 or b = (1/3)a

Stuck on a step? Read the free lesson: Substitution

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Also searched as: 4024/22/M/J/22 · 4024_s22_qp_22 · 4024 s22 22 · question 2.
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