Question

Multiply the pair conjugates using the Product of Conjugates Pattern (simplify) (rs-2/5)(rs+2/5)

Answer 1

In order to calculate the product of a pair of conjugate terms, we can use the pattern below:

$(a+b)(a-b)=a^2-b^2$

So we have:

$\begin{gathered} (rs-\frac{2}{5})(rs+\frac{2}{5}) \\ =(rs)^2-(\frac{2}{5})^2 \\ =r^2s^2-\frac{4}{25} \end{gathered}$