11. x= –22, y= –3
12.x= 5, y= –13/5
13.x= 17/23, y= –30/23
14.x= 7, y= 1
15.x= 4, y= –3
16.x= 2, y= 6
17.x= –19/7, –31,7
18.x= 31/34, y= 19/17
19.x=0, y=2
20.x= –1, y=4
