raise the vehicle

Stupid question im sure.I was wondering; since i can put the front of my car on ramps could i put the back wheels on ramps as well ? and if so can i jack up the car and place the ramps on the back as well as the front. I want to do exhaust work and think this would be easier. Like i said stupid question im sure> i just dont want to do it and get crushed or something

I would suggest jack stands. It is not advisable to put all four wheels on ramps.