Can I use the microwave to warm formula?

No. You should not warm formula in the microwave since the microwave can make hot spots inside the formula that you may not feel until it burns your baby's mouth. Better to warm them in a pan of hot water or running hot water.
No. The general rule is not to use a microwave oven to warm a bottle of breastmilk or formula. Microwave ovens do not warm evenly, so some parts of the bottle will be very hot while other parts still cold.
No. Microwaving formula or breastmilk may cause uneven heating and when you baby drinks a hot spot may cause a mouth burn. To heat the milk run warm water over the bottle or place in a bowl of warm water. If you are in a hurry there is no problem with feeding your baby room temperature milk.