Question

Find the square of 405 using identity (a+b)² = a² + 2ab + b²
Which of the following
$1002001$
$260100$
$164025$
$43681$


Answer
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Answer 1

Answer:

(400+5)^2

=400^2+2×400×5+5^2

=160000+4000+25

=164025