①×10得:2x+5y=0 ③
②得:5x+5-2y-34=0
5x-2y=29 ④
③×5-④×2得:10x+25y-10x+4y=-58
29y=-58
y=-2
把y代入③得:2x+5×(-2)=0
x=5
①×6得:3x+2y=12 ③
②×10得:2x+3y=12 ④
③×2-④×3得:6x+4y-6x-9y=24-36
-5y=-12
y=2.4
把y代入③得:3x+2×2.4=12
x=2.4
①得:x+y+19/6=7
x+y=23/6 ③
②得:x-2y+11/15=2
x-2y=19/15 ④
③-④得:x+y-x+2y=23/6-19/15
3y=77/30
y=77/90
把y代入④得:x-2×77/90=19/15
x=134/45