(1 5/8+19/24-1 1/12)*x=1

1) 1 5/8 + 19/24=13/8+19/24=39/24+19/24=58/24=29/12
2) 29/12-1 1/12=29/12-13/12=16/12=4/3
3) 4/3х=1
    х=1:4/3=1*3/4
    х=3/4

(1 5/8+19/24-1 1/12)*x=1
(13/8+19/24-13/12)*x=1
(39+19-26)/24*x=1
32/24*x=1
4/3*x=1
x=3/4