Question

please give answer.....​

Answer 1

Step-by-step explanation:

(x^2)^2 - (9y^2)^2

( a^2 - b ^2 ) = ( a+b) (a-b)

= (x^2 + 9y^2) ( x^2 - 9y^2)

Hope it will help you.

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Answer 2

Question :-

Factorise.

• ${x}^{4} - {81y}^{4}$

Solution :-

• ${x}^{4} - {81y}^{4}$

Here an identity will be used :-

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

${x}^{4} - {81y}^{4}$

$( {x}^{2})^{2} - ( {9y}^{2})^{2}$

$= ( {x}^{2} - {9y}^{2} )( {x}^{2} + {9y}^{2} )$

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$\huge\rm{Know~more}$

Some useful identities.

• $( {a} + {b})^{2} = {a}^{2} + {b}^{2} + 2ab$
• $( {a} - {b})^{2} = {a}^{2} + {b}^{2} - 2ab$
• ${a}^{3} - {b}^{3} = (a - b)( {a}^{2} + {b}^{2} + ab)$
• ${a}^{3} + {b}^{3} = (a + b)( {a}^{2} + {b}^{2} - ab)$
• $( {a + b})^{3} = {a}^{3} + {b}^{3} + 3ab(a + b)$
• $( {a - b})^{3} = {a}^{3} - {b}^{3} - 3ab(a - b)$