Question

Find the value of (49)${}^2$.

Answer 1

(49)${}^2$ can be written as (50 - 1)${}^2$.
Using the identity, $(a-b{)}^2=(a{)}^2-2ab+(b{)}^2$,
(50 - 1)${}^2$ = (50)${}^2$-2(1)(50)+(1)${}^2$ = 2401.