2x+y=10 4y+z=21 5x-z=10 求X.Y.Z各为多少,

若4x-3y-6z=0,x+2y-7z=0,求代数式5x*5x+2y*2y-z*z/2x*2x-3y*3y-10z*10 已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z均不为0,求3x*x+2y*y+5z*z/5x*x+y*y- 1.x+y+z=30,3x+y-z=50,x,y,z为非负数,求5x+4y+2z取值范围. 已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z都不为0,求（3x*x+y*y+4z*z）/（5x*x+y* (x-2y+z)/9=(2x+y+3z)/10=-(3x+2y-4z)/3=1 连等,求x,y,z, 已知x,y,z满足3x+7y+z=5 4x+10y+z=3 求x+y+z的值 已知x、y、z满足{3x+7y+z=5 ,求x+y+z的值 {4x+10y+z=3 x+y=10 y+z=15 z+x=20 求x,y,z等于多少? X+Y+Z=200,1/3X+4Y+5Z=200,求X,Y,Z等于多少? (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 x/10 = y/8 =z/9 求x+2y+3z/y-5z