Question

Que.4 evaluate: 65×55.​

Answer 1

Answer:

Using Formula (x+a)(x+b) = x

2

+(a+b)x+ab

Writing 55 as 50+5 and 45 as 50−5

⇒ (50+5)(50−5) = 50

2

+[5+(−5)]50+(5)(−5)

= 2500+(0)50−25

= 2475

The answer is 2475