The left rear window works ok?
You would have to check for power and ground at the right front and right rear window motor. If there is power and ground going there, then you have two faulty motors. With no power/ground - you may have a master switch issue, or a wiring issue.
Easy way to get a quick idea if the motors are weak or faulty - turn on the dome light and watch it. Then engage the switches for the faulty windows. If the dome light dims when pressing the button, you probaby have a faulty motor, as it is drawing power enough to dim the light, but not operating. Best of luck.