Vibration/ shaking 30-40 mph

When I accelerate in the lower rpm’s between 30-40 mph range my car starts to shake.. if I let off the gas or accelerate fast it doesn’t happen. Just recently had the tires rotated and balanced and it didn’t fix the problem.

 

Are they new tires or from the factory? How long has the vibration been happening?

 

I got these tires in May of last year, this just started the last 3 weeks - took it into the shop last week for maintenance oil change, balance and rotate. They said the tires were not balanced and it fixed the problem 15 minutes after picking it up it started back up

 

id take it back and tell them what is going on. road force balancing is recommended.