Paper 1 · Algebra ⏱ Tested in 5 exam questions since 2023 Lesson 15 of 23

Algebra 15 – Modulus Equations

In this lesson you’ll learn to

  • Interpret |x| as a size or distance that can never be negative
  • Solve modulus equations by splitting into ± cases or by squaring both sides
  • Always square both sides when a modulus meets an inequality
  • Solve |f(x)| = |g(x)| by squaring to remove both moduli at once

Most recent exam questions

  • 2025 Paper 1 Q1(a) — modulus inequality
  • 2025 Paper 1 Q1(b) — modulus inequality — Paul's universal rule from Algebra 15: always square
  • 2025 Paper 1 Q10(c) — apply the |a| + |b| = n rule to a specific point
  • 2023 Paper 1 Q1(a) — modulus equation
  • 2023 Paper 2 Q4(a)(ii) — apply the perpendicular distance formula (page 18) to convert "distance from line to poi…
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