1、x^2y-6xy^2+9y^22、（y^2+4^2）-16y^23、(a-b)m^2+(b-a)n^24、x^3-2x[2分之1x^2-3)(6分之1x-1)-4分之1x]5、(a+1)^2-(1-a)(-a-1)6、[(2xy+3)(2xy-3)+（xy+3^2）]÷xy

化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， 1-2/x+y=xy,4y+6x=xy.求xy的解? .(x+y-2)(x+y-2xy)+(xy-1)^2 9xy(x-y)(x+1)-3y(x-y)(3x+2y)+6y的平方(x-y)(x+1),因式分解 (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) -9y^2+6xy-x^2 因式分解30题(要过程)am+an+bm+bn x^2+5y-xy-5x x2+xy+2xz+x (a+b)x-(b+a)y -12x(x-y)-(y-x)x^2 2x^2+4x+2 x(x+z)-y(y+z) 2(x^2-3ab)+x(4a-3b) 4x^2+12xy+9y^2-25 x^4-16 16x^4-1 x^2+9x+8 x^2-10xy+24y^2 2x^2+15xy-8y^2 3x^2-6xy+3y^2 24x^2+22x-21 -x^2+4xy- ①(9x²y-6xy²)÷3xy ②(3x²y-xy²+2分之1xy)÷(-2分之1xy) {(x-y/x^2-2xy+y^2)-(xy+y^2/x^2-y^2)}*(xy/y-1) (9x^2y-6xy^2)/3xy [ 2x-6y][8-9xy]÷xy等于? x^2-xy-6y^2+3xy+y+2 4xy-[(x²+5xy-y²)-(3xy-1/2y)]x=3,y=-6 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 2x²+5xy+2y²+3x+3y-9 6x²+13xy+6y²+5x+5y+1 9x^2y+y^3-6xy^2因式分解