Question
Using the formula $(a-b)^2=\left(a^2-2 a b+b^2\right)$, evaluate:
$(689)^2$
$(689)^2$
✓
Answer
$(689)^2$
$=(700-11)^2$
$=(700)^2-2 \times 700 \times 11+(11)^2$
$=490000-15400+121$
$=474721$
$=(700-11)^2$
$=(700)^2-2 \times 700 \times 11+(11)^2$
$=490000-15400+121$
$=474721$
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