Question

please give me answer​

Answer 1

Step-by-step explanation:

$\bf{\underline{\underline\red{To\:Find:-}}}$

• (a) (x² - y²) ( x² + y²)

• (b) (x + 2) ( x - 2)

• (c) $\rm \bigg(\dfrac{2}{b} - \dfrac{5}{c} \bigg)\bigg(\dfrac{2}{b} + \dfrac{5}{c} \bigg)$

• (d ) (ab + 9) (ab - 9)

$\bf{\underline{\underline\green{Solution:-}}}$

a) (x² - y²) ( x² + y²)

Identity

$\boxed{ \leadsto\rm(a + b)(a - b) = {a}^{2} - {b}^{2} }$

Here:-

• a = x²

• b = y²

(x² - y²) ( x² + y²)

= (x²)² - (y²)²

= x⁴ - y⁴

__________________

b) (x + 2) (x - 2)

Here:-

• a = x

• b = 2

(x + 2) (x - 2)

= (x²) - (2)²

= x² - 4

_________________

c) $\rm \bigg(\dfrac{2}{b} - \dfrac{5}{c} \bigg)\bigg(\dfrac{2}{b} + \dfrac{5}{c} \bigg)$

= $\rm \bigg(\dfrac{2}{b} \bigg)^{2} - \bigg(\dfrac{5}{c} \bigg)^{2}$

= $\rm \dfrac{4}{b^{2}} - \dfrac{25}{c^{2} }$

_________________

d) (ab + 9) (ab - 9)

Here:-

• a = ab

• b = 9

(ab + 9) (ab - 9)

= (ab)² - (9)²

= a²b² - 81

Answer 2

Answer:-

Using,

${\color{Blue} (a+b)(a-b)=a^{2}-b^{2}}$

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

=> $(x^{2})^{2}=(y^{2})^{2}$

=> $x^{4}-y^{4}$

__________________________

2) (x+2)(x-2)

=> x²- 4

__________________________

3) $\left ( \frac{2}{b}-\frac{5}{c} \right )\left ( \frac{2}{b}+\frac{5}{c} \right )$

=> $\frac{2}{b}^{2}-\frac{5}{c}^{2}$

=> 4/b²-25/c²

__________________________

4) (ab-9)(ab+9)

=> ab²-9²

=> a²b²-81