1.
1) 2/7+2=2 2/7=16/7
2) 4/(16/7)=(4*7)/16=28/16=7/4
3) 7/4 - х=(7-4х)/4
4) 2х-1/4=(8х-1)/4
(7-4х)/4 : (8х-1)/4=6
(7-4х)/4 * 4/(8х-1)=6
(7-4х)/(8х-1)=6
7-4х=6(8х-1)
7-4х=48х -6
52х=13
х=13:52
х=1/4
2.
.............
(х-5)/3 - (х-7)/4= - 3/4*((х+5)/6 - (х+7)/3)
(х-5)/3 - (х-7)/4= - ((х+5)/8 - (х+7)/4)
8(х-5) - 6(х-7)= - 3(х+5)+6(х+7)
8х-40 -6х+42= - 3х-15+6х+42
2х-3х=40-15
- х=25
х= - 25