To solve these equations, we want to find the common denominator in each expression.

For the first equation:
1/3 + 1/? = ?/15
Multiplying both sides by 15? to get rid of the denominators, we get:
5? + 15 = 3?
Subtracting 5? from both sides, we get:
15 = -2?
Dividing by -2 on both sides, we get:
? = -15/2

For the second equation:
1/? + 1/9 = ?/45
Multiplying both sides by 45? to get rid of the denominators, we get:
45 + 5? = 9?
Subtracting 5? from both sides, we get:
45 = 4?
Dividing by 4 on both sides, we get:
? = 45/4

Therefore, the solutions for the equations are:
1) ? = -15/2
2) ? = 45/4