Step-by-step explanation:
In the given molecule of 5-isopropyl-2-methyl-3-nonene their are nine carbon atom attached in straight chain. 
- 3-nonene means that double bond is between the third carbon and forth carbon atom.
 
- Isopropyl group 
 on the fifth carbon atom in the chain 
- Methyl group 
on second carbon atom in the chain. 
Th structure of the given organic molecule is attached as an image.