Question

(a) (3х +5у)^2 +(3x -5y)^2
plz help​

Answer 1

To solve -

Find the value of -

( 3x + 5y )² + ( 3x - 5y )²

Solution -

Here we have to find the value of -

( 3x + 5y )² + ( 3x - 5y )²

=> [ 3x ]² + [ 5y ]² + 2[ 3x ][ 5y ] + [ 3x ]² + [ 5y ]² - 2[ 3x ][ 5y ]

=> 2 { [ 3x ]² + [ 5y ]² }

=> 2 { 9x² + 25y² }

=> 18x² + 50y² .

This is the required answer .

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Additional Information -

( a + b )² = a² + 2ab + b²

( a - b )² = a² - 2ab + b²

( a + b )( a - b ) = a² - b²

( a + b )³ = a³ + 3ab ( a + b ) + b³

( a - b )³ = a³ - 3ab ( a + b ) - b³

( a + b + c )³ = a³ + b³ + c³ + 3 ( a + b )( b + c )( c + a )

a³ + b³ + c³ - 3abc = ( a + b + c )( a² + b² + c² - ab - bc - ca )

When a + b + c = 0 ,

a³ + b³ + c³ = 3abc .

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Answer 2

18x square + 50y square is the answer.

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