(1/4+1/5 )*x=1 4/5
5+4 9
--------- * x = --------
20 5
9/20 * x = 9/5
x = 9/5 : 9/20
x = 9/5 * 20/9
x = 4
-------------------------
(1/4+1/5)*4=9/5 ili 1 4/5
(2 1/12 - 1 5/6)*x=3/4
25-22/12 * x = 3/4
3/12 * x = 3/4
x = 3/4 : 3/12
x = 3/4 * 12/3
x = 3
----------------------------
(2 1/12 - 1 5/6)*3=3/4