9. х=8 3/10-5 4/5
х=7 13/10-5 8/10
х=2 5/10; х=2.5
10. х=4 5/13 - 1 6/13+1 1/39
х=4 15/39 -1 18/39 + 1 /39=3 (54-18+1)/39=3 37/39
