三元一次方程(需过程)(1)x+2y+2z=33x+y-2z=72x+3y-2z=10(2)x-y=-12x+y+3z=5x+y-z=1(3)x+y=8y+z=-1x+z=5(4)x-y=2z-x=3y+z=-1(5)x-y-z=23x+5y+7z=244x-y+2z=26要过程!最好用代入消元法和加减消元法做!

Question

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!急!

Answer 1

(1)x+2y+2z=3 ①
3x+y-2z=7 ②
2x+3y-2z=10 ③
①+②,①+③,得
4x+3y=10 ④
3x+5y=13 ⑤
④*3-⑤*4,得
y=2 x=1
将x=1 y=2代入①,得 z=-1
(2)x-y=-1 ①
2x+y+3z=5 ②
x+y-z=1 ③
②+③*3,得
5x+4y=8 ④
①*4+④,得
x=4/9 y=13/9
将 x=4/9 y=13/9 代入③,得 z=8/9
(3)x+y=8 ①
y+z=-1 ②
x+z=5 ③
②-③,得
y-x=-6 ④
①+④,得
y=1 x=7
将 y=1代入② 得 z=-2
(4)x-y=2 ①
z-x=3 ②
y+z=-1 ③
②-③,得
-y-x=4 ④
①+④,得
y=-3 x=5
将 x=5代入② 得 z=2
(5)x-y-z=2 ①
3x+5y+7z=24 ②
4x-y+2z=26 ③
①*5+②,①-③,得
4x+z=17 ④
x+z=8 ⑤
④-⑤,得
x=3 z=5
将 x=3 z=5代入①,得 y=-4