Using identity (a-b)²=a²-2ab+b² find the value of (98)².

Solution

(98)² can be further written as (100 – 2)²
By comparing the above equation with the identity, we get
a = 100 and b = 2
(98)²=(100)²−2(100)(2)+(2)²
=10000−400+4
=9604