解方程组;1.x+y+z=26,x-y=1,2x-y+z=18 2.5x+y+z=1,2x-y+2z=1,x+5y-z=4.

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解方程组;1.x+y+z=26,x-y=1,2x-y+z=18 2.5x+y+z=1,2x-y+2z=1,x+5y-z=4.

解方程组;1.x+y+z=26,x-y=1,2x-y+z=18 2.5x+y+z=1,2x-y+2z=1,x+5y-z=4.
解方程组;1.x+y+z=26,x-y=1,2x-y+z=18 2.5x+y+z=1,2x-y+2z=1,x+5y-z=4.

解方程组;1.x+y+z=26,x-y=1,2x-y+z=18 2.5x+y+z=1,2x-y+2z=1,x+5y-z=4.
1) x+y+z=26---(1)
x-y=1---(2)
2x-y+z=18---(3)
(1)+(2)==>2X+Z=27---(4)
(1)+(3)==>3X+2Z=44---(5)
(4)*2-(5)==>X=10,Z=7,Y=9
2) 5x+y+z=1--(1)
2x-y+2z=1---(2)
x+5y-z=4----(3)
(1)+(2)==>7X+3Z=2---(4)
(1)*5-(3)==>24X+6Z=1---(5)
(4)*2-(5)==>-10X=3,
X=-3/10,Z=41/30,Y=17/15

要吐了、1、z=7 x=10 y=9 2、x=7/22 b=17/33 c=29/66

(1)x+y+z=26
(2)x-y=1
(3)2x-y+z=18 与(1)相减得(4)
(4)x-2y=-8与(2)相减
y=9 代入到(2)
x=10 分别代入到(1)
z=26-9-10=7
(1)5x+y+z=1两边同时×2得:10x+2y+2z=2 与(2)相减得(5)8x+3y=1
(2)2x-y+2z=1
(...

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(1)x+y+z=26
(2)x-y=1
(3)2x-y+z=18 与(1)相减得(4)
(4)x-2y=-8与(2)相减
y=9 代入到(2)
x=10 分别代入到(1)
z=26-9-10=7
(1)5x+y+z=1两边同时×2得:10x+2y+2z=2 与(2)相减得(5)8x+3y=1
(2)2x-y+2z=1
(3)x+5y-z=4与(1)相加得(4)
(4)6x+6y=5
(5)的两边同时×2得(6)
(6)16x+6y=2 与(4)相减
10x=-3
x=-3/10 代入到(5)
3y=1-8x=1-8*(-3/10)=17/5
y=17/15 分别代入到(1)
z=1-5*(-3/10)-17/15=41/30

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