计算：3x-(4y-2x+1)

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 分解因式计算:x^2(x-y)+(y-x)=?x^3+x^2+1\4x=?(2x+y)^2-(x-2y)^2=? 计算(x+4)·(-2x)-(x+1)(x-1)+(-3x+2)(x+1)； （3x-y)(y+3x)-(4x-3x)( (1)计算：a-(a^2)/(a+1)-1 (2)计算：3x/(x-4y)+(x+y)/(4y-x)-7y/(x-4y) (x-3y)(y+2x)-(4y-3x)(3x+4y)计算 计算【3(x-y)^2(x+y)^-2/4(x+y)^2(x-y)^-2】^-2 计算（2x-3y)(x+4y)-(3x+y)(x-2y) 计算：3x-(4y-2x+1) (1)(2x-3y)的平方-(y+3x)(3x-y) (1~4是计算) (2)[(x-y)的平方+(x+y)的平方](x 计算:(-x-2y) * (3x-y) 计算(4x^2-2x^3+6x)/(-2x)-(x-1)^2y^2-4/y^2-y-6)+(y+2/y-3)/(y+1/ 计算1/6x-4y +1/6x+4y — 3x/4y^2-9x^2