Use the direct method to evaluate : (2+a) (2−a) - Vidyadip

Question

Use the direct method to evaluate : $(2+a) (2−a)$

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Answer

Note: $(a+b) (a−b)$
$= a^2 − b^2(2+a) (2−a)$
$= (2)^2 − (a)^2$
$= 4 − a^2$

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