Moderate -0.8 This is a straightforward algebraic expansion requiring multiplication of three binomials and collection of like terms. It's a routine C1 skill with no problem-solving element—students simply apply the distributive property twice and simplify, making it easier than average.
reasonable attempt, even if an error at an early stage
means more marks not available
Question 1:
1 | 2x3 + 9x2 + 4x – 15 | 3 | as final answer; ignore ‘= 0’;
B2 for 3 correct terms of answer seen or
for an 8-term or 6 term expansion with
at most one error:
or M1 for correct quadratic expansion
of one pair of brackets;
or SC1 for a quadratic expansion with
one error then a good attempt to
multiply by the remaining bracket | correct 8-term expansion:
2x3 + 6x2 − 2x2 + 5x2 − 6x + 15x − 5x − 15
correct 6-term expansions:
2x3 + 4x2 + 5x2 − 6x + 10x − 15
2x3 + 6x2 + 3x2 + 9x − 5x − 15
2x3 + 11x2 − 2x2 + 15x − 11x − 15
for M1, need not be simplified;
ie SC1 for knowing what to do and making a
reasonable attempt, even if an error at an early stage
means more marks not available