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

Answer:

Your Question :---

Subtract 21² from 22² without actually calculating the squares.

$\bold{\boxed{\huge{\boxed{\orange{\small{\boxed{\huge{\red{\bold{\:Answer}}}}}}}}}}$

We know that ,

(a²-b)² = (a+b)(a-b)

so,

let a = 22 and b = 21 and putt values in above formula , we get,

(22²-21²) = (22+21)(22-21)

(22²-21²) = (43)(1)

(22²-21²) = 43 (Ans)

Some additional formulas you must aware of :-----

[1] ( a + b )² = a² + 2ab + b²

[2] ( a – b )² = a² – 2ab + b²

[3] ( a + b )³ = a³ + 3a² b + 3ab² + b³

[4] ( a – b )³ = a ³ – 3a² b + 3ab² – b³

[5] ( a + b )( a ² - ab + b² ) = a³ + b³

[6] ( a – b )( a ² + ab + b² ) = a³ – b³