Question

3x²y-{2x²y-3(2xy-x²y-x²y)-xy}

Answer 1

3x²y-{2x²y-3(2xy-x²y-x²y)-xy}
=3x²y-(2x²y-6xy+6x²y-xy)
=3x²y-(8x²y-7xy)
=3x²y-8x²y+7xy
=-5x²y+7xy

追问

你好像写错了

追答

那里错？

追问

我打错了对不起
3x²y-{2x²y-3(2xy-x²y)-xy}

追答

3x²y-{2x²y-3(2xy-x²y)-xy}
=3x²y-(2x²y-6xy+3x²y-xy)
=3x²y-(5x²y-7xy)
=3x²y-5x²y+7xy
=-2x²y+7xy