Using suitable identity evaluate 81²
Answers
Answered by
10
Answer:
81sq = (80+1)sq
=80sq +1sq+2×80×1
=6400+1+160
=6561
Step-by-step explanation:
we have used the identity
(a+b)whole square= a square + b square +2ab
Answered by
5
Answer:
6561
Step-by-step explanation:
(80+1)²
Using
(a+b)²=a²+b²+2ab
(80+1)²=(80)²+(1)²+2*80*1
=6400+1+160
=6561
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