求一道代数式的值.
问题描述：
求一道代数式的值.
2x²y+｛2xy-[3x²y-2(-3x²y+2xy)]-4xy²}
化简这个多项式,过程不用了,
答
2x²y+｛2xy-[3x²y-2(-3x²y+2xy)]-4xy²}
=2x²y+2xy-3x²y-6x²y+4xy-4xy²
=-7x²y+6xy-4xy²