Question

Simplify : (x+y)^3-(x-y)^3-6y(x^2-y^2)

please answer ​

Answer 1

$=(x+y) </p><p>3</p><p> −(x−y) </p><p>3</p><p> −6y(x </p><p>2</p><p> −y </p><p>2</p><p> )</p><p>=(x+y) </p><p>3</p><p> −(x−y) </p><p>3</p><p> −6y(x−y)(x+y)</p><p>=(x+y) </p><p>3</p><p> −(x−y)((x−y) </p><p>2</p><p> +6y(x+y))</p><p>=(x+y) </p><p>3</p><p> −(x−y)(x </p><p>2</p><p> +y </p><p>2</p><p> −2xy+6xy+6y </p><p>2</p><p> )</p><p>=(x+y) </p><p>3</p><p> −(x−y)(x </p><p>2</p><p> +7y </p><p>2</p><p> +4xy)</p><p>=x </p><p>3</p><p> +y </p><p>3</p><p> +3x </p><p>2</p><p> y+3xy </p><p>2</p><p> −x </p><p>3</p><p> −7xy </p><p>2</p><p> −4x </p><p>2</p><p> y+x </p><p>2</p><p> y+7y </p><p>3</p><p> +4xy </p><p>2</p><p> </p><p>=8y </p><p>3$

Answer 2

(x+y)^3-(x-y)^3-6y(x^2-y^2)

let..(x+y) be z

= (x+y)^3-(x+y)^3-6y(x+y)^2

=. z^3-z^3-6y*z^2 ans