OCR MEI C1 — Question 5 5 marks

Exam BoardOCR MEI
ModuleC1 (Core Mathematics 1)
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicFactor & Remainder Theorem
TypeFully specified polynomial: verify factor and solve
DifficultyModerate -0.8 This is a straightforward application of the factor theorem requiring substitution to verify a factor, then polynomial division and solving a quadratic. It's routine C1 material with clear steps and no problem-solving insight needed, making it easier than average but not trivial since it requires multiple techniques.
Spec1.02f Solve quadratic equations: including in a function of unknown1.02j Manipulate polynomials: expanding, factorising, division, factor theorem

5 You are given that \(\mathrm { f } ( x ) = x ^ { 3 } - 7 x + 6\).
  1. Show that ( \(x - 2\) ) is a factor of \(\mathrm { f } ( x )\).
  2. Solve the equation \(\mathrm { f } ( x ) = 0\).

Question 5:
Part (i):
AnswerMarks Guidance
\(f(2) = 8 - 14 + 6 = 0\) so \((x-2)\) is a factorB1 Total: 1
Part (ii):
AnswerMarks Guidance
\(f(x) = (x-2)(x^2+2x-3) = 0\)M1 A1
\(\Rightarrow (x-2)(x-1)(x+3) = 0\)A1
\(\Rightarrow x = 1, 2, -3\)B1 Complete factorisation. Total: 4
# Question 5:

## Part (i):
$f(2) = 8 - 14 + 6 = 0$ so $(x-2)$ is a factor | B1 | **Total: 1**

## Part (ii):
$f(x) = (x-2)(x^2+2x-3) = 0$ | M1 A1 |
$\Rightarrow (x-2)(x-1)(x+3) = 0$ | A1 |
$\Rightarrow x = 1, 2, -3$ | B1 | Complete factorisation. **Total: 4**

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5 You are given that $\mathrm { f } ( x ) = x ^ { 3 } - 7 x + 6$.\\
(i) Show that ( $x - 2$ ) is a factor of $\mathrm { f } ( x )$.\\
(ii) Solve the equation $\mathrm { f } ( x ) = 0$.

\hfill \mbox{\textit{OCR MEI C1  Q5 [5]}}