Question

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

Answer 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....

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

Answer 2

22² - 21²

so we will use the identity

a² - b² = (a+b)(a-b)

= (22 + 21) (22 - 21)

= (43)(1)

= 43

so the difference is 43