Slash is a 70-base power move on a Zangoose (a good Physical Attacker) with the Critical
Hit ratio boosted twice (once by Slash's secondary effect, once by the Dire Hit).
Therefore, under these circumstances,

Your best bet is to use something with very high defense, something your team lacks. I
suggest replacing either Loudred, Delcatty, or Linoone (probably Linoone, since it works
best as an HM slave) with Aron/Lairon, Graveler/Golem, or something else like that with a
high defense stat.

Alternatively, you could use a Sableye. Although Sableye doesn't have a great defense,
Normal-type attacks (like Slash) won't hit it.

Use an x-defense

its the trainer

u need more training (try using weaknesses and resistances)

Just train your pokemon more!!!

DUMMY!!!

well thats a rubbish team to start with. you dont just have to stick with pokemon you find
in the first ten mi***es of the game. and there all really weak anyway. get new ones. and
be at least level 34.