To represent the sum of the three investments, we can set up the following equation based on the information provided:
Given:
- Total investment: \( 380000 \)
- Investments: \( x \) (6.5%), \( y \) (9%), and \( z \) (8%)
The equation for the total sum of the investments will be:
\[ x + y + z = 380000 \]
So, the equation representing the sum of the three investments is:
\[ x + y + z = 380000 \]