解三元一次方程组:(1)x+2y+3z=11x-y+4z=10x+3y+2z=2(2)x:y=3:5y:z=5:6x+y+2z=40(3)x+y-z=2y+z-x=4z+x-y=6谢谢!

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解三元一次方程组:(1)x+2y+3z=11x-y+4z=10x+3y+2z=2(2)x:y=3:5y:z=5:6x+y+2z=40(3)x+y-z=2y+z-x=4z+x-y=6谢谢!
解三元一次方程组:
(1)
x+2y+3z=11
x-y+4z=10
x+3y+2z=2
(2)
x:y=3:5
y:z=5:6
x+y+2z=40
(3)
x+y-z=2
y+z-x=4
z+x-y=6
谢谢!

解三元一次方程组:(1)x+2y+3z=11x-y+4z=10x+3y+2z=2(2)x:y=3:5y:z=5:6x+y+2z=40(3)x+y-z=2y+z-x=4z+x-y=6谢谢!
(1)
x+2y+3z=11(1)
x-y+4z=10(2)
x+3y+2z=2(3)
(1)-(2)得,3y-z=1,(4)
(3)-(2)得,4y-2z=-8,即2y-z=-4,(5)
(4)-(5),得y=5,
代人得z=14,
x=-39
所以x=-39
y=5,
z=14
(2)
x:y=3:5(1)
y:z=5:6(2)
x+y+2z=40(3)
由(1)得,x=(3/5)y,
由(2)得,z=(6/5)y,
代人到(3),得,
(3/5)y+y+2*(6/5)y=40.
解得,y=10,
代人,得x=6,z=12
所以x=6,
y=10,
z=12,
(3)
x+y-z=2(1)
y+z-x=4(2)
z+x-y=6(3)
(1)+(2)+(3),得,
x+y+z=12,(4)
(4)-(2),得x=4,
(4)-(3),得y=3,
(4)-(1),得z=5
所以:
x=4,
y=3,
z=5