Question

Find the square of 23 using identity

Answer 1

using (a+b)²=a²+b²+2ab

$= {23}^{2} \\ = {(20 + 3)}^{2} \\ = {20}^{2} + {3}^{2} + 2 \times 20 \times 3 \\ = 400 + 9 + 120 \\ = 529$