先化简,再求值:5x²-[2xy-3(1/3xy+2)+4x²]求过程和答案,

问题描述:

先化简,再求值:5x²-[2xy-3(1/3xy+2)+4x²]求过程和答案,

解原式=5x2-[2xy-xy-6+4x2]
=5x2-xy+6-4x2
=x2-xy+6