1/2x^2y^4-8x^2

因式分解：-1/2*x*x*x*y+1/4*x*x*y*y-1/8*x*x*x*y*y*y 化简(2x/(x+y)-4x/(y-x))/8x(x^2-y^2)得 计算:1/(x-y)-1/(x+y)-2y/(x^2+y^2)-4y^3/(x^4+y^4)-8x^7/(x^8+y^8) [(2x-y)^2-y(y-4x)-8x]其中x=-1/2 x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² 9y=3x-(x-1),4(x+y)-(2x+4)=8y 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) [(2x+y)²-y(y+4x)-8x】/4x,其中x=-1,y=2005 急 1.(x^3-x^2-4x+1)/(x^2-3x+2)-(x^3-2x^2-9x+21)/（x^2-5x+6）+（x^2-3x+8）/（x^2-4x+3）2.{(x^2)/（x-y)}*{y/(x+y)}-{(x^4y)/(x^4-y^4)}÷{（x^2/x^2+y^2）^2} 若x-y=1 化简（x+y)(x^2+y^2)(x^4+y^4)(x^8+y^8)(x^16+y^16) {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 化简(4x-2y)-[5x-(8y-2x-x-y)]+x 化简(4x-2y)-﹛5x-[8y-2x-(x+y)]-x﹜ (1)x^2*x^8+x^13/x^3 (2)a^19/a^12/a^3 (3) (x-2y)^5/(2y-x)^3 (4)(x-y)^5/(x-y) (5)(x-y)^6/(y-x)^4 x^3+2x^2y-4x-8y 化简:[(2x+y)^2-y(y+4x)-8x]/2x 其中x=1/2 4x-3y/x-2y÷6y-8x/y-2x 81/8*(-x-y)^6*(x-y)^3*4/9(x+y)^4*(y-x)^2