(-3x-4y+5z)^2

(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 已知x:y:z=3:4:5,3x+2y-4z=18.求：x+y+z. 2x+5y+4z=6,3x+y-7z=-4,x+y-z=? 已知2x+5y+4z=6 3x+y-7z=-4求x+y-z {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 x/3=y/4=z/5,求x+y+z/3x-2y+z的值, 若x/3=y/4=z/5,求x+y+z/3x-2y+z的值. 已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z 2x+y+3z＝383x+2y+4z＝564x+y+5z＝66 5x+3y+2z=2011 4x+6y+7z=2012 求x+y+z 2x+5y+4z=0,3x+y-7z=0,则x+y-z=? 已知x/4=y/5=z/6 求x+y+z/3x-2y+z的值