1) (2+3)/6 *x= 3.75
5/6*x=3.75
x=3.75*6:5
x= 4,5 (или 9/2)
2) (3/5-1/4)*x=4.9
(12/20-5/20)*x =4.9
7/20*x=4.9
x= 4.9*20:7
x= 14
3) (7/8-1/5)*x=8.1
(35/40-8/40)*x=8.1
27/40*x=8.1
x= 8.1*40:27
x= 39
4) (4-17/7)*x=33/14
(28/7-17/7)*x=33/14
11/7*x=33/14
x=(14*11):(33*7)
x= 1.5 (или 3/2)