1>Tínk:
1, \(\left(x+y\right)^3-\left(x-y\right)^3\)
2, 64-24y+\(3y^2-\dfrac{1}{8}y^3\)
3, \(216x^3+18x^2y+\dfrac{1}{2}xy^2+\dfrac{1}{216}y^3\)
4, \(\left(2x+y\right)^3-3.\left(x+y\right).\left(x-y\right)\)
5, \(\left(x-y\right)^3+3.\left(x+y\right).\left(x^2+y^2\right)\)
Các bạn ơi: