(2x+y-z+5)(2x-y+z+5)

x/2=y/3=z/5 x+3y-z/x-3y+z 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) 因式分解：25x y^2 z^2 (x+y-z)-30xyz(z-x-y)^2+5x y z^3 (z-x-y) (y-x)/(x+z-2y)(x+y-2z)+(z-y)(x-y)/(x+y-2z)(y+z-2x)+(x-z)(y-z (x+y+z)^5-(x+y-z)^5-(x+z-y)^5-(z+y-x)^5, {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 x,y,z正整数 x>y>z证明 x^2x +y^2y+z^2z>x^(y+z)*y^(x+z)*z^(x+y) 化简(y-x)(z-x)/(x-2y+z)(x+y-2z)+（z-y)(x-y)/(x-2z+y)(y+z-2x)+(x (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai (x-2y+z)(x+y-2z)分之（y-x)(z-x) + (x+y-2z)(y+z-2x)分之(z-y)(x-y) {5X+Y+Z①X+5Y+Z=-2②X+Y+5Z=10③ x+y+z=2 x-3y+2z=1 2x+2y+z+5 要具体步骤..