(i) 712 = (70 + 1)2
= (70)2 + 2(70) (1) + (1)2
= 4900 + 140 + 1 = 5041
Note : [(a + b)2 = a2 + 2ab + b2 ]
(ii) 992 = (100 − 1)2
= (100)2 − 2(100) (1) + (1)2
= 10000 − 200 + 1 = 9801
Note : [(a − b)2 = a2 − 2ab + b2 ]
(iii) 1022 = (100 + 2)2
= (100)2 + 2(100)(2) + (2)2
= 10000 + 400 + 4 = 10404
Note : [(a + b)2 = a2 + 2ab + b2 ]
