计算：1/6x-4y"+"1/6x+4y"-"2y/4y^2-9x^2"

计算(4x^2-2x^3+6x)/(-2x)-(x-1)^2y^2-4/y^2-y-6)+(y+2/y-3)/(y+1/ {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 计算1/6x-4y +1/6x+4y — 3x/4y^2-9x^2 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 计算：（3x-4y）-[-（2y+x）+（x-3y）]-6x 已知4x=9y求(1)x+y/y (2)y-x/2x 计算6x³y^6÷(1/2)y³÷(-3x²y)-(12x^4y^6-8x²y^ 因式分解 （1）.(x+y)(x+y-6)+9 （2）.x²-16y²-x-4y 计算:(x-y)^2*(y-x)^2*(x-y)^6 1) (2x+5y)(2x-5y)(-4x^2-25y^2) 2) [（x+y)(x-y)-(x-y)^2+2y(x-y 3x+2=y 5X+4=Y 7X+6=Y 9X+8=y 11x=y要如何计算 计算:(x-2y)(1+x+2y+4y^2+2xy+x^2)