CAIE P2 2020 March — Question 2 6 marks

Exam BoardCAIE
ModuleP2 (Pure Mathematics 2)
Year2020
SessionMarch
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPolynomial Division & Manipulation
TypeFactorisation After Division or Remainder
DifficultyModerate -0.8 This is a straightforward polynomial division question with a direct 'hence' part. Part (a) is routine algebraic manipulation requiring polynomial long division or inspection. Part (b) simply requires recognizing that the remainder being 18 means the equation factors as (x²+5x+6)(quotient)=18, leading to standard quadratic solving. No novel insight needed, just methodical application of standard techniques.
Spec1.02f Solve quadratic equations: including in a function of unknown1.02j Manipulate polynomials: expanding, factorising, division, factor theorem

2
  1. Find the quotient when \(4 x ^ { 3 } + 17 x ^ { 2 } + 9 x\) is divided by \(x ^ { 2 } + 5 x + 6\), and show that the remainder is 18 .
  2. Hence solve the equation \(4 x ^ { 3 } + 17 x ^ { 2 } + 9 x - 18 = 0\).

Question 2(a):
AnswerMarks Guidance
AnswerMark Guidance
Carry out division as far as \(4x + k\)M1
Obtain quotient \(4x - 3\)A1
Confirm remainder is \(18\)A1 AG necessary detail needed
Total3
Question 2(b):
AnswerMarks Guidance
AnswerMark Guidance
State or imply equation is \((4x-3)(x^2+5x+6)=0\)B1FT Following *their* quotient from part (a)
Attempt solution of cubic equation to find three real rootsM1
Obtain \(-3,\ -2,\ \frac{3}{4}\)A1
Total3
## Question 2(a):

| Answer | Mark | Guidance |
|--------|------|----------|
| Carry out division as far as $4x + k$ | M1 | |
| Obtain quotient $4x - 3$ | A1 | |
| Confirm remainder is $18$ | A1 | AG necessary detail needed |
| **Total** | **3** | |

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## Question 2(b):

| Answer | Mark | Guidance |
|--------|------|----------|
| State or imply equation is $(4x-3)(x^2+5x+6)=0$ | B1FT | Following *their* quotient from part **(a)** |
| Attempt solution of cubic equation to find three real roots | M1 | |
| Obtain $-3,\ -2,\ \frac{3}{4}$ | A1 | |
| **Total** | **3** | |
2
\begin{enumerate}[label=(\alph*)]
\item Find the quotient when $4 x ^ { 3 } + 17 x ^ { 2 } + 9 x$ is divided by $x ^ { 2 } + 5 x + 6$, and show that the remainder is 18 .
\item Hence solve the equation $4 x ^ { 3 } + 17 x ^ { 2 } + 9 x - 18 = 0$.
\end{enumerate}

\hfill \mbox{\textit{CAIE P2 2020 Q2 [6]}}