Question 949128
12(6 4/9)=(12*6)+12(4/9)=72+48/912x + 131 = 189 + 3x
9x=58
x=58/9
CHECK:
{{{72(48/9) + 131 = 189 +  18(12/9)}}} 
Your problem is here:
12(6 4/9)=(12*6)+12(4/9)=72+48/9
Your answer of 77 22/3 is off. Maybe just a multiplication error. 
The 19 1/3 is the same as 18 12/9 so that part is all right.