The image you provided shows a system of equations involving variables $A$, $B$, and $C$. Here's what I can interpret:

1. $13A + 14B + 15C + 20 = 243$
2. $15A + 10B + 8C + 9 = 104$
3. $45A + 10B + 18C + 50 =$ (the right-hand side is missing)

I'll help you solve the first two equations, then we can work on the third equation once it's clarified.

Step 1: Simplify the equations

First equation: $13A + 14B + 15C + 20 = 243$ Subtract 20 from both sides: $13A + 14B + 15C = 223$

Second equation: $15A + 10B + 8C + 9 = 104$ Subtract 9 from both sides: $15A + 10B + 8C = 95$

Now, let me know the right-hand side of the third equation, or I can proceed with solving these two for $A$, $B$, and $C$ if that's what you prefer.

Do you have any questions or would you like to see the next steps in solving these equations? Here are a few questions to expand your understanding:

1. How do we approach solving systems of linear equations with multiple variables?
2. What methods can be used to eliminate variables in such systems (e.g., substitution or elimination)?
3. How would you describe the process of reducing equations to make solving easier?
4. What role do constants like 20 or 9 play in the simplification process?
5. How does adding or subtracting terms affect both sides of the equation?

Tip: Simplifying equations by isolating variables or constants can make solving systems of equations much easier!