Question

Factorise {a}^{4} - 16" align="absmiddle" class="latex-formula">
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Answer 1

Since both terms are perfect squares, factor using the difference of squares formula,  a ^2 − b^ 2 = ( a + b ) ( a − b )  where  a = a ^2  and  b = 4 . ( a ^2 + 4 ) ( a + 2 ) ( a − 2 )