Two jacks will lift the weight but it will not be stable! Be very carefull and don't try anything that rocks the car. If you are asking this so that you can do the brake job you mentioned yesterday, your car will probably fall of the jack when you go to losen the caliper bolts or put a wheel back on. Get some jack stands! Again weight is not the issue. the car can easily rock and fall off the jacks. I have seen this happen first hand.