A2 | Maths Made Easy

A2

Question: Expand pqr(5pr+5r5-25pqr).

Solution: We have to multiply the term outside the bracket, pqr, by each term inside the bracket. Make sure you’re familiar with the laws of indices before trying to tackle this question.

So, we get

\begin{aligned}pqr(5pr +5r^5 -25pqr)&=pqr\times 5pr + pqr\times 5r^5 - pqr\times 25pqr \\ &=5p^{2}qr^{2} + 5pqr^6 - 25p^{2}q^{2}r^{2} \end{aligned}