4. (1/3+1/4+1/5)·x=1 19/75
20·1+15·1+12·1 94 47 94
-------------------------- ·x= ---------, ------- x = -------------
60 75 60 75
94 47 94 60 94·60 2·4
x= ------------ :------------ = -------------- · ----------- = ------------- =- ------- =1,6
75 60 75 47 75·47 5
5).(9/2) :x= 3 19/28- 1 3/4= 2 (19-21) /28=1 (47-21)/28= 1 26/28= 1 13/14
x= (9/2):(27/14)=9·14/27·2 7/3==2 1/3
6).x-2 4/15= 3 2/3: 3 5/13
x- 2 4/15=(11/3):(44/13)=(11/3)·(13/44)= 11·13/3·44=13/12
x=13/12+34/15= (13·5+4·34)/60=(65+136)/60=201/60=3 21/60= 3 7/20=
= 3,35