(1)x+y-z=0 2x-y+3z=2 x-4y-2z+6=0(2)3x+y=6 x+2y-z=5 5x-3y+2z=4(3)x+y+z=-1 4x-2y+3z=5 y-z=8-2x(4)2x+3y=5 3y-4z=3 4z+5x=7三元一次方程,千万别用科学计算器来算裁图,
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(1)x+y-z=0 2x-y+3z=2 x-4y-2z+6=0(2)3x+y=6 x+2y-z=5 5x-3y+2z=4(3)x+y+z=-1 4x-2y+3z=5 y-z=8-2x
(4)2x+3y=5 3y-4z=3 4z+5x=7三元一次方程,千万别用科学计算器来算裁图,
这种三元一次方程组的解法常用高斯消元法,四个题解法都是一样的.现给出第(1)题的过程:
由x+y-z=0可得z=x+y,代入剩余两个方程可得:2x-y+3(x+y)=2,x-4y-2(x+y)+6=0,整理得:5x+2y=2,
x+6y=6(这个式子可以两边同乘5得:5x+30y=30),由5x+2y=2,5x+30y=30两式相减消去5x,可得28y=28,y=1,再由x+6y=6(或5x+2y=2)可得x=0,而z=x+y=1,解完!详细过程就是这样,参照着做就可以了,写了这么多,其他三个方程直接给出答案:(2) x=2,y=0,z=-3; (3)x=3,y=-1,z=-3;
(4)x=5/3,y=5/9,z=-1/3;
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x+y+z=6 x+2y+3z=14 y+1=z
方程组 (1) x+2y-3z=12 x-3y+2z= - 13 x-y-z=0 (2) x+ y=z 5x-y+z=18 2x+5y+3z= -1
(1)X+Y=15,Y+Z=-6,Z+X=7.(2)X+Y=-14,Y+Z=-7,Z+X=9.(3)X+Y=0,Y+Z=-1,Z+X=-1.