化简运算：(2xy-3x^2y^2)-(5x+3xy-y^2x^2) （5y+3x-15z^2）-（12y+78x+z^2）怎样化简?
问题描述：
化简运算：(2xy-3x^2y^2)-(5x+3xy-y^2x^2) （5y+3x-15z^2）-（12y+78x+z^2）怎样化简?
答
(2xy-3x²y²)-(5x+3xy-y²x²)=2xy-3x²y²-5x-3xy+x²y²=(2xy-3xy)+(-3x²y²+x²y²)= -xy-2x²y²(5y+3x-15z²)-(12y+78x+z²)=5y+3x-15z...