Edexcel F2 2014 June — Question 2 7 marks

Exam BoardEdexcel
ModuleF2 (Further Pure Mathematics 2)
Year2014
SessionJune
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicInequalities
TypeRational inequality algebraically
DifficultyStandard +0.3 This is a standard rational inequality requiring sign analysis and critical point identification. While it involves case work (multiplying by a squared term or considering sign changes), it's a routine Further Maths technique with straightforward algebraic manipulation and no conceptual surprises.
Spec1.02g Inequalities: linear and quadratic in single variable1.02k Simplify rational expressions: factorising, cancelling, algebraic division

2. Use algebra to find the set of values of \(x\) for which $$\frac { 6 } { x - 3 } \leqslant x + 2$$

Question 2:
AnswerMarks Guidance
Answer/WorkingMark Guidance
\(x+2-\frac{6}{x-3} \geq 0 \Rightarrow \frac{(x+3)(x-4)}{x-3} \geq 0\)M1 Attempt to combine fractions and factorise the numerator
\(x=-3,\ x=4\)A1, A1 Correct critical values
\(x \geq 4\)A1ft Follow through their 4
\(x=3\)B1 Identifies 3 as a critical value
\(-3 \leq x < 3\)M1A1 M1: Attempt inside region; A1: Correct inequality
Way 2:
AnswerMarks Guidance
Answer/WorkingMark Guidance
\(6(x-3) \leq (x+2)(x-3)^2 \Rightarrow (x-3)(4-x)(x+3) \geq 0\)M1 Multiplies both sides by \((x-3)^2\) and attempt to factorise
\(x=-3,\ x=4\)A1, A1 Correct critical values
\(x \geq 4\)A1ft Follow through their 4
\(x=3\)B1 Identifies 3 as a critical value
\(-3 \leq x < 3\)M1A1 M1: Attempt inside region; A1: Correct inequality
Way 3:
AnswerMarks Guidance
Answer/WorkingMark Guidance
\(x-3>0 \Rightarrow 6 \leq (x+2)(x-3) \Rightarrow (x-4)(x+3) \geq 0\)M1 Multiplies both sides by \((x-3)\), attempt to factorise, must state \(x-3>0\)
\(x=4\)A1 Correct critical value
\(x \geq 4\)A1ft Follow through their 4
\(x=3\)B1 Identifies 3 as a critical value
\((x-3<0) \Rightarrow 6 \geq (x+2)(x-3),\ x=-3\)A1 Correct critical value
\((x+2)(x-3) \leq 6 \Rightarrow (x-4)(x+3) \leq 0 \Rightarrow -3 \leq x < 3\)M1A1 M1: Attempt inside region; A1: Correct inequality
# Question 2:

| Answer/Working | Mark | Guidance |
|---|---|---|
| $x+2-\frac{6}{x-3} \geq 0 \Rightarrow \frac{(x+3)(x-4)}{x-3} \geq 0$ | M1 | Attempt to combine fractions and factorise the numerator |
| $x=-3,\ x=4$ | A1, A1 | Correct critical values |
| $x \geq 4$ | A1ft | Follow through their 4 |
| $x=3$ | B1 | Identifies 3 as a critical value |
| $-3 \leq x < 3$ | M1A1 | M1: Attempt inside region; A1: Correct inequality |

**Way 2:**

| Answer/Working | Mark | Guidance |
|---|---|---|
| $6(x-3) \leq (x+2)(x-3)^2 \Rightarrow (x-3)(4-x)(x+3) \geq 0$ | M1 | Multiplies both sides by $(x-3)^2$ and attempt to factorise |
| $x=-3,\ x=4$ | A1, A1 | Correct critical values |
| $x \geq 4$ | A1ft | Follow through their 4 |
| $x=3$ | B1 | Identifies 3 as a critical value |
| $-3 \leq x < 3$ | M1A1 | M1: Attempt inside region; A1: Correct inequality |

**Way 3:**

| Answer/Working | Mark | Guidance |
|---|---|---|
| $x-3>0 \Rightarrow 6 \leq (x+2)(x-3) \Rightarrow (x-4)(x+3) \geq 0$ | M1 | Multiplies both sides by $(x-3)$, attempt to factorise, must state $x-3>0$ |
| $x=4$ | A1 | Correct critical value |
| $x \geq 4$ | A1ft | Follow through their 4 |
| $x=3$ | B1 | Identifies 3 as a critical value |
| $(x-3<0) \Rightarrow 6 \geq (x+2)(x-3),\ x=-3$ | A1 | Correct critical value |
| $(x+2)(x-3) \leq 6 \Rightarrow (x-4)(x+3) \leq 0 \Rightarrow -3 \leq x < 3$ | M1A1 | M1: Attempt inside region; A1: Correct inequality |

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2. Use algebra to find the set of values of $x$ for which

$$\frac { 6 } { x - 3 } \leqslant x + 2$$

\hfill \mbox{\textit{Edexcel F2 2014 Q2 [7]}}