Question

How to evaluate (81)2-(19)2 by identity 3ed

Answer 1

$\huge \sf(81)2 - (19)2 \\ \\ \huge \to \: \sf 2(81 - 19) \\ \\ \huge \to \: \sf2 \times (62) \\ \\ \huge \to \: \sf \frac{10}{5} \times 62 \\ \\ \huge \to \: \: \: \: \: \: \sf\frac{620}{5} \\ \\ \huge \to \: \: \sf \red{124}$