To solve this equation, we need to first simplify the left side by combining the fractions and then solve for x.

19/31 + 21/31 + x + 7/31 = 37 8/31

(19/31 + 21/31 + 7/31) + x = 37 8/31

47/31 + x = 37 8/31

Now, we need to convert 37 8/31 to an improper fraction.

37 8/31 = (31*37 + 8)/31 = 1155/31

Therefore, the equation becomes:

47/31 + x = 1155/31

Subtracting 47/31 from both sides:

x = 1155/31 - 47/31

x = 1108/31

So, the solution to the equation is x = 1108/31.