the total of salaries must be x + y = 38, here x is the sary of paralegal and y is the salary of assistant.
We have too the salary of paralegal is 12 more than the assist so x=y+12
Solve the system, you can replace x into the first equation:
y+12+y=38
2y=38-12
y=26/2
y=13 this is the salary of assistant