(7x^2y^3-8x^3y^2z)/8x^2y^2计算

计算：3x-2y- [-4x+(z+3y)] (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) 2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X 解三元一次方程：x+y-z=0,2x+y+z=7,x-3y+z=8 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 {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) 计算（x+2y-3z)的平方+（x-2y+3z)(x+2y-3z) (x+2y+3z)-(3x+2y-z)+(2x-3y+4z) 用直式计算 ①x+y+z=6 3x-y+2z=12 x-y-3z=-4 ②x+y-z=2 4x-2y+3y+8=0 x+3y-2z-