to use a setup live

ok, i have alot of stuff i would like to know. i will put them in order..

1.at practice since im in a room, if i wanted my sound from my guitar amp to come out of the pa speakers rather than the amp so i can have the signal come from the amp and into the pa speakers, how do I do that without getting sound out of the guitar amp and just out the PA speakers.

2.Playing live ,does it matter how powerful your guitar amp is? if you are just gonna run the amp into a powerful power amp that will go to the PA speakers, you know.

3. What is an Equalizer for live performances?

4.what is an amp modeler for your guitar amp?

5.Whats up with micing your amp? Does it really matter because if you run the signal to the the PA system why would you have to worry about micing your amp?

Please answer these like the way i asked them like....

1. **********so on
2.*********so on

2. No, i doesnt matter how powerful your amp is if there is a PA system. If the quality of the sound you getting is fine there is no problem with just using a 15watt amp or less.

4. An amp modeler is an a piece of equipment which simulates other amps by trying to give you the closest sound to the amp you want. Something like the PX4 does this.

Thats all i can really answer so far. I'm not too sure about anything else, sorry.

3. An equalizer would be useful to change the tone from ur amp slightly by changing the bass and treble etc. It would be used for the same reason live probably. Perhaps if the PA system was crap you could regain your tone using an equalizer.