I seriously doubt it would be a comfortable experience even if you could do it. How many days are you trekking?
Do you really need a 70L bag PLUS a laptop bag? You are looking at a combined weight of 20+kg. Do you even need a laptop? If you are trekking over several days, how are you going to power/charge your laptop? Why risk damaging or losing your laptop on a trek in the first place?
I think you should simplify and reduce. Bring a smaller bag, bring less crap, and ditch the laptop. Many things can be done on your phone anyway. When packing, don't ask "will I use this". Ask "Will I use this often enough to justify lugging it over a long distance and long time". If you use something 0 or 1 time over the whole trip, better don't bring it. You probably won't miss it. Exceptions that you should bring regardless are small first aid kit, emergency supplies, or very small/light items that increase your comfort/safety.
I'll be going trekking with a 70L backpack and a daypack, which is my laptop backpack. Is it viable to bring these 2 bags along for the trek? Along with some camping?