Let's break down the equations one at a time.
Part 1: Equation for the sum of the three investments.
Given that the total amount invested is $380,000, we can write the equation as:
\[
x + y + z = 380000
\]
Part 2: Equation for the sum of the returns from all three investments.
To find the returns from each investment, we can calculate them based on their respective interest rates.
- The return from the investment at 6.5% is \(0.065x\).
- The return from the investment at 9% is \(0.09y\).
- The return from the investment at 8% is \(0.08z\).
According to the problem, the total annual earnings from these properties is $30,550. Therefore, we can write the equation for the total returns as:
\[
0.065x + 0.09y + 0.08z = 30550
\]
Now, we have the two equations needed for parts (a) and (b):
- \(x + y + z = 380000\)
- \(0.065x + 0.09y + 0.08z = 30550\)