Structures and IUPAC names of some hydrocarbons are given below. Explain why the names given in the parentheses are incorrect.
`underset(["and not 3,4,7-Trimethyloctane"])underset(2,5,6- "Trimethyloctane")(CH_(3)-underset(CH_(3))underset(|)(CH)-CH_(2)-CH_(2)-underset(CH_(3))underset(|)(CH)-underset(CH_(3))underset(|)(CH)-CH_(2)-CH_(3))`
`underset(["and not 5-Ethyl-3-methylheptane"])underset("3-Ethyl-5-methylheptane")(CH_(3)-CH_(2)-underset(CH_(2)CH_(3))underset(|)(CH)-CH_(2)-underset(CH_(3))underset(|)(CH)-CH_(2)-CH_(3))`

Explanation

To solve the problem, we need to analyze the structures and the IUPAC names given for the hydrocarbons and explain why the names in parentheses are incorrect.

### Step 1: Analyze the first structure and name

1. **Identify the structure**: The first structure is a hydrocarbon with a total of 8 carbon atoms in the longest chain, which is octane.
2. **Number the carbon chain**: We can number the carbon chain from either end. Let's number it from the left:
- 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8
3. **Identify substituents**: The substituents (methyl groups) are located at:
...