Question

Evaluate by using suitable identity:(399)^2

Answer 1

Answer as follows -
(399)^2

=(300^2)+(99^2)
=90000+9801
=99801

Hope it'll help you out buddy

Answer 2

$(a - b) = a {}^{2} - 2ab + b {}^{2}$
$399 { }^{2} = (400 - 1) { }^{2} = 400 {}^{2} - 2 \times 400 \times 1 + 1 { }^{2} = 160001 - 800 = 159201$