Using the formula (a-b)^2= (a^2-2 a b+b^2 ), evaluate: (689)^2 - Vidyadip

Question

Using the formula $(a-b)^2=\left(a^2-2 a b+b^2\right)$, evaluate:
$ (689)^2$

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Answer

$ (689)^2$
$ =(700-11)^2 $
$ =(700)^2-2 \times 700 \times 11+(11)^2 $
$ =490000-15400+121 $
$ =474721 $

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