CAIE P2 2024 November — Question 2 4 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2024
SessionNovember
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicModulus function
TypeSolve |linear| compared to linear: algebraic only
DifficultyStandard +0.3 This is a straightforward modulus inequality requiring students to consider two cases (x-7 ≥ 0 and x-7 < 0), solve linear inequalities in each case, and combine the solutions. While it requires systematic case-work, the algebraic manipulation is routine and the question type is a standard textbook exercise, making it slightly easier than average.
Spec1.02l Modulus function: notation, relations, equations and inequalities

2 Solve the inequality \(| x - 7 | > 4 x + 3\).

Question 2:
AnswerMarks Guidance
AnswerMark Guidance
Attempt solution of equation or inequality, where signs of \(x\) and \(4x\) are differentM1
Obtain \(\frac{4}{5}\)A1 OE
... and finally no other valueA1
Conclude \(x < \frac{4}{5}\)A1 Allow \(\left(-\infty, \frac{4}{5}\right)\)
Alternative Method:
AnswerMarks Guidance
AnswerMark Guidance
State or imply non-modulus equation \((x-7)^2 = (4x+3)^2\) or inequalityB1
Attempt solution of three-term quadratic equation or inequalityM1
Obtain finally \(\frac{4}{5}\) onlyA1
Conclude \(x < \frac{4}{5}\)A1 Allow \(\left(-\infty, \frac{4}{5}\right)\)
## Question 2:

| Answer | Mark | Guidance |
|--------|------|----------|
| Attempt solution of equation or inequality, where signs of $x$ and $4x$ are different | M1 | |
| Obtain $\frac{4}{5}$ | A1 | OE |
| ... and finally no other value | A1 | |
| Conclude $x < \frac{4}{5}$ | A1 | Allow $\left(-\infty, \frac{4}{5}\right)$ |

**Alternative Method:**

| Answer | Mark | Guidance |
|--------|------|----------|
| State or imply non-modulus equation $(x-7)^2 = (4x+3)^2$ or inequality | B1 | |
| Attempt solution of three-term quadratic equation or inequality | M1 | |
| Obtain finally $\frac{4}{5}$ only | A1 | |
| Conclude $x < \frac{4}{5}$ | A1 | Allow $\left(-\infty, \frac{4}{5}\right)$ |

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2 Solve the inequality $| x - 7 | > 4 x + 3$.\\

\hfill \mbox{\textit{CAIE P2 2024 Q2 [4]}}