计算：(1) x+2y+(4y^2/x-2y) (2) (x/x^2-1)除以(x^2+4x+3)/(x^2+2x+1) (3) 12/(m^2-9)加上2/(3-m) m第3小题m不等于正负3x+2y+4y^2/(x-2y) 第一小题

计算:(4xy(x-y)^-1+(x(y^-1)-(x^-1)y)/((x^-1)+(y^-1)))*(x+y)^-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:2xy/(x+y)².(x+y)/4y 计算(x+y-1)^2 计算:(x-2y)(x+y)-2y(1-4y)= 计算（2x-3y)(x+4y)-(3x+y)(x-2y)（2x-3y)(x+4y)-(3x+y)(x-2y) 计算:y-x分之x+y+x-y分之y-y-x分之2x-y 计算:(x-2y)(1+x+2y+4y^2+2xy+x^2) (x-3y)(y+2x)-(4y-3x)(3x+4y)计算 计算:(x-y)^2*(x+y)^3*(-x-y)^3*(y-x)^4 计算：[（x+y）³-2(x+y)²-4(x+y)]÷（x+y) 计算[(x+y)的立方-2(x+y)的平方-4(x+y)]÷(-x-y) (x+y)(x-y)-(2x+y)(x-y+1)计算要过程 计算2x/x-y 计算:(x+2y)(2x-y) 计算:(x+3y)(2x-y) 计算:(2x-3y)(x+y) 计算:(-x-2y) * (3x-y)