3xy^2-4x^3y-x+y^2-1 这是几次几项式? 怎么得的?如题卷子答案是：四次五项式我认为是三次五项式

因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² x²-y²+5x+3y+4（x+y-2xy)(x+y-z)+(xy-1）² XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2) 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= x-y=1,xy=2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 .已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 (-2xy+2x+5y)-(3xy+2y-2x)-(x+4y+xy)其中x-y=4xy=-1 化简求值x-4y/2x-7xy+3y×x-2xy-3y/2x+3xy-2y÷3x-6y/4x-4xy+y,其中：x=1999,y=-1 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] 已知x-y=3,xy=1,求（-2x+2x+3y)-(3xy+2y-2x)-(x+4y+xy) 因式分解x^2y^2+x^2y+xy^2+3xy+x+y+1 化简2(x²y+xy)-3(x²y-xy)-4x²y 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y 计算：（1）8x^2y^2*(-3x/4y^5) (2)(x+y)^2/xy-y^2*(y-x)^2/xy+y^2