Moderate -0.8 This is a straightforward completing the square question with standard coefficient manipulation and direct reading of the minimum from completed square form. It requires routine algebraic technique with no problem-solving insight, making it easier than average but not trivial due to the non-unit leading coefficient requiring factorization.
Question 6:
6 | 3(x 2)2 7 isw or a = 3, b = 2 c = 7 www
7 or ft | 4
B1
[5] | B1 each for a = 3, b = 2 oe
and B2 for c = 7 oe
7
or M1 for or for 5 their a(their b)2
3
5
or for theirb2 soi
3
B0 for (2, 7) | condone omission of square symbol;
ignore ‘= 0’
may be implied by their answer
may be obtained by starting again eg
with calculus
Express $3x^2 - 12x + 5$ in the form $a(x - b)^2 - c$. Hence state the minimum value of $y$ on the curve $y = 3x^2 - 12x + 5$. [5]
\hfill \mbox{\textit{OCR MEI C1 Q6 [5]}}