Question

解三元一次方程：x+y=-3,y+z=-1,z+x=2

要过程，快快快快快快快

Answer 1

x+y=-3.........(1)
y+z=-1.........(2)
z+x=2.........(3)

(1)+(2)+(3)得
2x+2y+2z=-2
x+y+z=-1.........(4)

(4)-(1)得
z=2
(4)-(2)得
x=0
(4)-(3)得
y=-3

解得
x=0
y=-3
z=2