First Equation:

Simplify the equation (52+39)-c=15
91-c = 15

Now, isolate c by subtracting 91 from both sides:
-c = 15-91
-c = -76

Finally, multiply both sides by -1 to solve for c:
c = 76

Second Equation:

Simplify the equation x+(73-48)=82
x + 25 = 82

Now, isolate x by subtracting 25 from both sides:
x = 82 - 25
x = 57

Therefore, the solutions are:
c = 76
x = 57