.................................
5х+6 = 12,5х
5х-12,5х= -6
-7.5х = -6
х = 0,8
<span>8 1\2 -3 4\15- 1 7\30=8 15/30-3 8/30-1 7/30=8 15/30-4 15/30=4
(13-8 5/12)+(17 1/2-16 1/5)=(12 12/12-8 5/12)+(17 5/10-16 2/10)=4 7/12+1 3/10=
4 35/60+1 18/60=5 43/60
(63 2/3+3 1/8)-(13-10 5/9)=
(63 16/24+3 3/24)-(12 9/9-10 5/9)=
66 19/24-2 4/9=60 39/72-2 32/72=58 7/72</span>