My rules of dealing with infinity:
1) ∞ + C = ∞, where C is any number.
2) C * ∞ = ∞ , same as above
3) ∞^C = ∞, same as above
Because there are nothing bigger than infinity, adding something to infinity is still infinity. Imagine a wall is blocking your way (because no bigger than infinity)and there are someone pushing behind you(the addition/multiplication/exponent), and that guy pushing behind you won't make you penetrate through the wall...XD
So that's why (I think) the 3 rules are true.