Edexcel C2 — Question 1 5 marks

Exam BoardEdexcel
ModuleC2 (Core Mathematics 2)
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicFactor & Remainder Theorem
TypeRemainder condition then further work
DifficultyModerate -0.8 This is a straightforward application of the Remainder Theorem requiring direct substitution into f(-2) to find k, then substitution into f(2/3). Both parts are routine C2 exercises with no problem-solving insight needed, making it easier than average but not trivial since it requires careful arithmetic with fractions.
Spec1.02j Manipulate polynomials: expanding, factorising, division, factor theorem

  1. \(\quad \mathrm { f } ( x ) = 3 x ^ { 3 } - 2 x ^ { 2 } + k x + 9\).
Given that when \(\mathrm { f } ( x )\) is divided by ( \(x + 2\) ) there is a remainder of - 35 ,
  1. find the value of the constant \(k\),
  2. find the remainder when \(\mathrm { f } ( x )\) is divided by ( \(3 x - 2\) ).

AnswerMarks Guidance
(a) \(f(-2) = -35\) \(\therefore -24 - 8 - 2k + 9 = -35\), \(k = 6\)M1 A1 B1
(b) \(= f(\frac{2}{3})\) \(= 3(\frac{2}{3})^3 - 2(\frac{2}{3}) + 6(\frac{2}{3}) + 9 = \frac{8}{9} - \frac{8}{9} + 4 + 9 = 13\)M1 A1 (5)
(a) $f(-2) = -35$ $\therefore -24 - 8 - 2k + 9 = -35$, $k = 6$ | M1 A1 | B1

(b) $= f(\frac{2}{3})$ $= 3(\frac{2}{3})^3 - 2(\frac{2}{3}) + 6(\frac{2}{3}) + 9 = \frac{8}{9} - \frac{8}{9} + 4 + 9 = 13$ | M1 A1 | (5)
\begin{enumerate}
  \item $\quad \mathrm { f } ( x ) = 3 x ^ { 3 } - 2 x ^ { 2 } + k x + 9$.
\end{enumerate}

Given that when $\mathrm { f } ( x )$ is divided by ( $x + 2$ ) there is a remainder of - 35 ,\\
(a) find the value of the constant $k$,\\
(b) find the remainder when $\mathrm { f } ( x )$ is divided by ( $3 x - 2$ ).\\

\hfill \mbox{\textit{Edexcel C2  Q1 [5]}}