\(\left\{{}\begin{matrix}x-y=7\\\left(x-y\right)\left(x^2+xy+y^2\right)=133\end{matrix}\right.< =>\left\{{}\begin{matrix}x-y=7\\x^2+xy+y^2=19\end{matrix}\right.< =>\left\{{}\begin{matrix}x-y=7\\\left(x-y\right)^2-xy=19\end{matrix}\right.< =>\left\{{}\begin{matrix}x-y=7\\xy=30\end{matrix}\right.< =>\left\{{}\begin{matrix}x=7+y\\\left(7+y\right)y=30\end{matrix}\right.< =>\left\{{}\begin{matrix}x=7+y\\y^2+7y-30=0\end{matrix}\right.< =>\left\{{}\begin{matrix}x=7+y\\\left[{}\begin{matrix}y=3\\y=-10\end{matrix}\right.\end{matrix}\right.< =>\left\{{}\begin{matrix}\left[{}\begin{matrix}x=10\\x=-3\end{matrix}\right.\\\left[{}\begin{matrix}y=3\\y=-10\end{matrix}\right.\end{matrix}\right.\)Vậy....
