why are these compounds wrong? 1,1-dichloro-5-propylhexane & 2-methyl-4-chloro-3heptenoic acid. what are their correct names?

The structure of the acid is: CH3-CH2-CH2-CCL=CH-CH(CH3)COOH

1,1-dichloro-5-propylhexane
You have not chosen the longest C chain correctly:

C1 - C2 - C3 - C4 - C5- C
....... ....... ...... ..... ...l
..... ...... ..... ..... .... ..C6 - C7 - C 8
This shows what you call 5-propylhexane.
The longest C-chain has 8 C . The molecule is octane. I have numbered the C atoms for you so you can see the 8C chain
You have octane with a methyl group on C5 and 2 chlorines on C1
Name 1,1-dichlor-5methyloctane.

2-methyl-4-chloro-3heptenoic acid
I guess that this is what you want to name:
C - C - C = C - C - C – COOH
......l.. .... ...l
.... .C.... .....Cl

To name you start at the COOH group as being C1. Count back to fix the position of the = double bond . This is on C4 =C5
The chlorine is on C4 and the CH3 is on C6
Name: 4-chloro -6-methyl -4heptenoic acid

The name 1,1-dichloro-5-propylhexane is incorrect. The propyl group should be included in the longest chain of the molecules, and thus the longest chain should have 8 carbon atoms. The correct name should be :
1,1-dichloro-5-methyloctane

The name 2-methyl-4-chloro-3heptenoic acid is also incorrect. The groups in the prefixes are arranged in alphabetical order. "Methyl" begin with "m" while "chloro" begins with "c", and thus "4-chloro" should be put in front of "2-methyl". Besides, a hyphen is missed after the number "3". The correct name should be :
4-chloro-2-methyl-3-heptenoic acid

The structures of the two compounds are shown in the following diagram :
https://c2.staticflickr.com/8/7488/27012560563_599a1c6e9d_b.jpg