Question

can anyone please tell me a formula through which I could solve this question
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Answer 1

Answer:

take its root for example 2 sq = 2×2 like that

Answer 2

Hope this helps you ;)

Using (a)^2 - (b)^2 = ( a + b )( a - b )

${(41)}^{2} - {(40)}^{2}$

$= (41 + 40)(41 - 40)$

$= (81)(1)$

$= 81$