Moderate -0.8 This is a straightforward application of the binomial theorem requiring identification of the correct term and calculation of one coefficient. It's easier than average as it involves only substitution into the binomial formula with small numbers and no algebraic manipulation beyond the expansion itself.
B3 for 720; M1 for each of \(3^2\) and \(\pm2^3\) or \((-2x)^3\) or \((2x)^3\), and M1 for 10 or \((5\times4\times3)/(3\times2\times1)\) or for 1 5 10 10 5 1 seen but not for \(^5C_3\)
## Question 15:
$-720\ [x^3]$ | **4** | B3 for 720; M1 for each of $3^2$ and $\pm2^3$ or $(-2x)^3$ or $(2x)^3$, and M1 for 10 or $(5\times4\times3)/(3\times2\times1)$ or for 1 5 10 10 5 1 seen but not for $^5C_3$ | Total: **4**
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