waecmaths question:
Simplify ${{(x-3y)}^{2}}-{{(x+3y)}^{2}}$
Option A:
$2(x+3y)$
Option B:
$2(x-3y)$
Option C:
$-12xy$
Option D:
$6xy$
waecmaths solution:
$\begin{align} & {{(x-3y)}^{2}}-{{(x+3y)}^{2}}=(x-3y-x-3y)(x-3y+x+3y) \\ & =(-6y)(2x) \\ & =-12xy \end{align}$
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