Why accelgor not learning extreme speed?

Question

with base speed is 145 I think its possible to learn extreme speed

Answer 1

It's not a question of speed, it's a question of moves. It can't learn Extreme Speed because it never could in the first place (barring hacks)

Answer 2

Firstly, it's one of the fastest Pokemon in the as is, I doubt it even needs it. Water shuriken already has priority, and since Accelgor is way better with SpAtk, shuriken would be a better move to use, even if Accelgor HAD extereme speed. Shuriken also counters fire types, and is deadly against any physical rock types like gigilith or ryperior.

Hope this helped!