x+2z=3 2y+z=7 2x-y-z=-5怎么解?_数学解答

x+2z=3 2y+z=7 2x-y-z=-5怎么解?

人气：141 ℃　时间：2020-02-06 05:05:01

解答

x+2z=3 (1)
2y+z=7 (2)
2x-y-z=-5 (3)
(1)*2-(3)得
y+5z=11(4)
(4)*2-(2)得
9z=15, z=5/3
y=11-5*5/3=8/3
x=3-2*5/3=-1/3