Question

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

Answer 1

Explanation:

$22 {}^{2} - {21}^{2}$

WE use identity here

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

so

${22}^{2} - {21}^{2} \\ (22 + 21)(22 - 21) \\ 43 \times 1 \\ 43$

Answer 2

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....

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