Question

) (2x - 7y)2 + 28xy = 4x2 + 49y2
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Answer 1

Final result of the question is. (2x-7y)Square

Answer 2

Solution:-

To Proof :-

(2x - 7y)² + 28xy = 4x² + 49y²

Proof:-

=)(2x - 7y)² + 28xy

=) (2x)² + (7y)² - 2(2x)(7y) + 28xy

=) 4x² + 49y² - 28xy + 28xy

=) 4x² + 49y².

Hence Proved!

Some Identities:-

(1) ( a+b)² = a² + b² + 2ab

(2) ( a-b)² = a² + b² - 2ab

(3) (a² + b²) = ( a+b)² - 2ab

(4) (a³ - b³) = ( a - b)( a² + b² + ab)

(5) ( a³ + b³) = ( a+b)( a² + b² - ab)

(6) ( a+b)³ = [ a³ + b³ + 3ab(a+b)]

(7) ( a-b)³ = [ a³ - b³ - 3ab( a-b)]

(8) ( a+b+c)² = a² + b² + c² + 2ab + 2bc + 2ca.