English, asked by bbjsjjsbabbaab, 11 months ago

Subtract the square of 21 from the square of 22 without actually calculating the squares. ​

Answers

Answered by Anonymous
1

Answer:

Given,

We need to Subtract the square of 21 from the square of 22 without actually calculating the squares.

Using the formula

 {x}^{2}  -  {y}^{2}  = (x + y)(x - y)

We get.....

 =  >  {(22)}^{2}  -  {(21)}^{2}  \\  =  > (22 + 21)(22 - 21) \\  =  > 43 \times 1 \\  =  > 43.

Answered by jaisika16
1

Answer:

we can write 21 as 20+1

if square(20+1)^{2}

we can write 22 as 20+2

if square

(20+2)^{2}

by using identity

(x+y)^{2} =x^{2} +2xy+y^{2}

(22)^{2} -(21)^{2}20^{2} +2*20*2+2^{2} -(20^{2} +2*20*1+1^{2} )\\=400+80+4-(400+40+1)\\=400+84-400-40-1\\

=43 is the correct answer

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