It appears you've uploaded an image containing text and some mathematical expressions. Let me extract and interpret the math content from it.

The key parts visible in the image include:

1. Some equations are listed with subscripts $y_1, y_2, y_3$, likely referring to a sequence or series.

   • $y_1 = 18$
   • $y_2 = 12$
   • $y_3 = 4$

2. A second part with another set of equations involving sums:

   • $s_5 = 35$
   • $s_{10} = 50$
   • $u_4 + u_9 = -275$
   • $u_5 = 130$

These seem to be equations related to an arithmetic or geometric sequence/series. If you need help solving them or analyzing the sequence type, let me know, and I can proceed with detailed calculations or explanations.

Would you like to work on one of these problems? Here are some questions to consider:

1. Do you want to find the general term formula for this sequence or series?
2. Are you trying to compute the sum of a certain number of terms in the sequence?
3. Would you like to solve for a missing term in one of the equations?
4. Should I explain how to solve for terms in arithmetic or geometric sequences?
5. Would you like help understanding how these equations are related?

Tip: When dealing with sequences, always check whether the pattern is arithmetic (difference between terms is constant) or geometric (ratio between terms is constant).