化简：（5x^2再*y+5xy-7x)-(4x^2再*y+5x-7x)的结果是?
问题描述：
化简：（5x^2再*y+5xy-7x)-(4x^2再*y+5x-7x)的结果是?
答对就赏,答错不赏
答
原式=(5x²y+5xy-7x)-(4x²y+5x-7x)
=5x²y+5xy-7x-4x²y-5x+7x
=(5x²y-4x²y)+5xy+(-7x-5x+7x)
=x²y+5xy-5x