Practicing Success
Simplify: $\left(x + y\right)^{3}− \left(x − y\right)^{3} − 6y\left(x^{2} − y^{2}\right)$ |
$8y^{3}$ $x^{3}$ $8x^{3}$ $y^{3}$ |
$8y^{3}$ |
$\left(x + y\right)^{3}− \left(x − y\right)^{3} − 6y\left(x^{2} − y^{2}\right)$ We know that, (x+y)3 = x3 + y3 + 3x2y + 3xy2 (x-y)3 = x3 - y3 - 3x2y + 3xy2 Applying the formula = = x3 + y3 + 3x2y + 3xy2 -(x3 - y3 - 3x2y + 3xy2) - 6y(x2 - y2) = x3 + y3 + 3x2y + 3xy2 - x3 + y3+ 3x2y - 3xy2 - 6yx2 + 6y3 After eliminating the terms we get, = 8y3 |