5x y-2z=17 2x-3y 7z=8 6x 2=3(y 6z)怎么算
问题描述：
5x y-2z=17 2x-3y 7z=8 6x 2=3(y 6z)怎么算
答
5x+y-2z=17 (1)
2x-3y+7z=8 (2)
6x+2=3(y+6z)
即6x-3y-18z=-2 (3)
(1)×3+(2)
17x+z=29 (4)
(3)-(2)
4x-25z=-10 (5)
(4)×25+(5)
429x=715
x=5/3
z=29-17x=2/3
y=17+2z-5x=10