x:y:z=4:5:6,x+y+z=75 是一个方程组说一下怎么来的 好不好

三元一次方程组,1.x-2y+z=9 2x+y+3z=10 3x+2y1.x-2y+z=92x+y+3z=103x+2y-z2.3x-5y+2z=14x+5y-z=5X-5y+3z=-23.7x+2y-z=76x-y+z=74x+3y+z=94.4x+3y-2z=-75x-6y+z=12x+z=-25.2x+3y-4z=-23x-2y+5z=262x+5z=31 x+y+z=4x-5y=y-x+6z,xyz不等0,x:y:z=? 已知3X=4X,5Y=6Z求X+Y：Y+Z x:y:z=4:5:6x+y+z=75 (x+y-z)(x-y+z)= x-y+z=-1 5x+2y-z=6 4x-3y+2z=-5 2x+5y+4z=6,3x+y-7z=-4,x+y-z=? x+y+z=1 4x+5y-z=6 x+2y-z=3 解方程组x+y+z=6 x+2y-3z=4 2x-y+z=5 {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 解方程组：x+y+z=4,x+y+2z=5,3x+y-z=6 已知2x+5y+4z=6 3x+y-7z=-4求x+y-z 已知x/4=y/5=z/6 求x+y+z/3x-2y+z的值 若x:y:z=3:4:5=6,求x-y+z分之x+y-z的值 已知x/4=y/5=z/6,求x+y+z/3x-2y+z的值. 5x+3y+2z=2011 4x+6y+7z=2012 求x+y+z 1.{x:y:z=3:4:5 2x+3y-5z=-142.{x-y-z=-1 3x+5y+7z=11 4x-y+2z=-13.{x+y=1 x+z=0 2x+y+2z=44.{x-y+z=-3 2x-y-z=-2 -3x+y+z=-15.{x-y+z=-3 3x+y-4z=6 2x+y-z=36.{x-2y+5z=16 2x+y-5z=7 2x-y+z=38 (x+y):(y+z):(z+x)=3:4:5 3x+y-z=-4已知(x+y):(y+z):(z+x)=3:4:5 ；3x+y-z=-4求x y z