Question

解方程 x+y-z=5,x-3y+2z=1,3x+2y-z=4

Answer 1

x+y-z=5,……① x-3y+2z=1,……② 3x+2y-z=4……③

①×2+②得,3x-y=11……④

③-①得,2x+y=-1……⑤

④+⑤得,5x=10,∴x=2

把x=2代人⑤得,4+y=-1,∴y=-5

把x=2 y=-5代人①得,2-5-z=5,解得z=-8

∴{x=2 y=-5 z=-8