a) \(x^6-y^6=\left(x^3-y^3\right)\left(x^3+y^3\right)\)
\(=\left(x-y\right)\left(x+y\right)\left(x^2-xy+y^2\right)\left(x^2+xy+y^2\right)\)
b) Đề sai, bạn vui lòng xem lại.
c) \(\left(xy+4\right)^2-\left(2x+2y\right)^2=\left(xy+4-2x-2y\right)\left(xy+4+2x+2y\right)\)
d) \(\left(a^2+b^2\right)^3-a^2b^2-b^2c^2-c^2a^2\)
Đề sai nốt!