1/х+3/2 2/5х=3/4
2 2/5+3
----------- =3/4
2 2/5х
5 2/5
------- =3/4
2 2/5х
2 2/5х=5 2/5:3/4
2 2/5х=36/5
12/5х=36/5
х=36/5:12/5=36/5*5/12
х=3
--------------------------------
проверка
1 3
-- + ---------=3/4
3 2 2/5*3
1 3
-- + ------- =3/4
3 36/5
1 5
--- + ----=3/4
3 12
4 5
--- +------=3/4
12 12
9/12=3/4
3/4=3/4