OCR MEI C1 2010 June — Question 8 4 marks

Exam BoardOCR MEI
ModuleC1 (Core Mathematics 1)
Year2010
SessionJune
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCompleting the square and sketching
TypeComplete the square
DifficultyModerate -0.8 This is a straightforward completing the square exercise with a leading coefficient, requiring factoring out the 5, completing the square on the remaining quadratic, and simplifying. It's a standard textbook procedure with clear steps and no problem-solving required, making it easier than average but not trivial due to the non-unit leading coefficient.
Spec1.02e Complete the square: quadratic polynomials and turning points

Express \(5x^2 + 20x + 6\) in the form \(a(x + b)^2 + c\). [4]

AnswerMarks Guidance
\(5(x + 2)^2 - 14\)4 B1 for \(a = 5\), and B1 for \(b = 2\) and B2 for \(c = -14\) or M1 for \(c = 6 - \text{their } ab^2\) or M1 for \([\text{their } a](6(\text{their } a - \text{their } b^2))\) [no ft for \(a = 1\)]
$5(x + 2)^2 - 14$ | 4 | B1 for $a = 5$, and B1 for $b = 2$ and B2 for $c = -14$ or M1 for $c = 6 - \text{their } ab^2$ or M1 for $[\text{their } a](6(\text{their } a - \text{their } b^2))$ [no ft for $a = 1$]
Express $5x^2 + 20x + 6$ in the form $a(x + b)^2 + c$. [4]

\hfill \mbox{\textit{OCR MEI C1 2010 Q8 [4]}}