[tex]\bf \textit{difference of squares}
\\ \quad \\
(a-b)(a+b) = a^2-b^2\qquad \qquad
a^2-b^2 = (a-b)(a+b)\\\\
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\cfrac{1}{p-2}-\cfrac{1}{p+2}\impliedby \textit{so let's use the }\stackrel{LCD}{(p-2)(p+2)}
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\cfrac{(p+2)~~-~~(p-2)}{(p-2)(p+2)}\implies \cfrac{\underline{p}+2~~\underline{-p}+2}{(p-2)(p+2)}\implies \cfrac{4}{p^2-2^2}\implies \cfrac{4}{p^2-4}[/tex]
