The number of blocks for supernetting must be power of 2 . Here we have 3 blocks which is not power of 2 so we cant aggregate them to a single supernetting network but still we can reduce no of entries in router by combining first two or last two network and they both combinely use as superneting.
network 1: 126.96.36.199/24
network 2: 188.8.131.52/24
network 3: 184.108.40.206/24
we can combine the first two network as 220.127.116.11/23
and last network 18.104.22.168/24
this two can be entries in the router which we minimize from 3 to 2 entries.
http://pages.cs.aueb.gr/courses/networks/Notes2016/Lecture11/subnetting-supernetting.pdf go to page number 31.