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Find all real zeros, using the given f(1)=0.

Read the idea, work independently, then explain what changed.

TOPIC 01

2022 JM02

f(1)=0 identifies one root, not all roots.

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Use one hint at a time. A correction explains what changed, not just the final answer.

01 / Standard#Your turn

Find all real zeros, using the given f(1)=0.

f(x)=x3−3x2+2f(x)=x^3-3x^2+2

Official paper · jm02-2022 · 2(a)(i) · PDF 4

Official original and suggested answers ↗ · Suggested answer PDF page 9

Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1
Divide by x−1.
Hint 2
Solve the remaining quadratic.
Worked solution
  1. Factor the cubic.

    f(x)=(x−1)(x2−2x−2)f(x)=(x-1)(x^2-2x-2)
  2. Apply the quadratic formula.

    x=1,x=1±3x=1,\quad x=1\pm\sqrt3

x=1, 1−√3, 1+√3.

Checks and common pitfalls: f(1)=0 identifies one root, not all roots.

Reasoning checklist · self / teacher assessment
  • Teaching assessment checklist, independently authored. Use the original paper for official marks.
  • Factor the cubic.
    f(x)=(x−1)(x2−2x−2)f(x)=(x-1)(x^2-2x-2)
  • Apply the quadratic formula.
    x=1,x=1±3x=1,\quad x=1\pm\sqrt3

Think first. Reveal a hint when the class is ready.

Focus on one question

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Curriculum and source notes ↗