3x+7y+z=3.15和4x+10y+z=4.2组成一个方程组的解是几?x=? y=? z=?

已知3x+7y+z=315和4x+10y+z=420,求x+y+z 3x+7y+z=3.15和4x+10y+z=4.2组成一个方程组的解是几?x=? y=? z=? 若x,y,z满足3x+7y+z=1和4x+10y+z=200,则x+3y分之2000x+2000y+2000z的值为? 若3x+7y+z=5,4x+10y+z=3,则x+y+z=? 解方程组：3x+7y+z=31.5,4x+10y+z=42求 x+y+z 解方程组：3x+y=9和10x-11y=30,x+2y+4z=17和2x+y+z=7和3x+y+2z=11(写过程） 解方程组：3x+y=9和10x-11y=30,x+2y+4z=17和2x+y+z=7和3x+y+2z=11(写过程） 谢了3x+7y+z=315 4x+10y+z=4203x+7y+z=3154x+10y+z=420 三元一次方程(需过程)(1)x+2y+2z=3 3x+y-2z=7 2x+3y-2z=10 (2)x-y=-1 2x+y+3z=5 x+y-z=1 (3)x+y=8 y+z=-1 x+z=5(4)x-y=2 z-x=3 y+z=-1(5)x-y-z=2 3x+5y+7z=24 4x-y+2z=26要过程!最好用代入消元法和加减消元法做! 已知x、y、z满足{3x+7y+z=5 ,求x+y+z的值 {4x+10y+z=3 已知x,y,z满足3x+7y+z=5 4x+10y+z=3 求x+y+z的值 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z 已知,方程组:4x-3y-7z=0 x+2y=10z 则(x-y+z)÷(x+y+z)=—— (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 4x-3y-3z=0 x-3y+z=0 并且X Y Z不等于0 求x:z 和y:z的值 方程组｛4x-3y-3z=0,x-3y+z=0,(x.y.z不等于0),求x/z和y/z的值? 若X:Y:Z=5:6:7那么(Y-X):(Y+Z)和(X+2Y+3Z):(3X+2Y+Z) (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian