Is invasion attack multiplied by attack boosters? is the boost from mutagenic cartridges multiplied by attack boosters?

As far as I understand it, attack and invasion attack are two different stats. And as such multipliers for one does not multiply for the other. However, taking into consideration that Attack goes into Invasion attack, multipliers will still help.
So no and no.

Your attack works into your Invasion attack. So yes and no.

invasion attack has been asked a lot of times. right now only dan knows the true equation on this matter.

the only thing for sure is that the more of this that you have the better your chances. (I know its an obvious matter)

Buffed Non-Invasion Attack = regular attack * regular attack buffs
Buffed Invasion Attack = ((regular attack * regular attack buffs) + invasion only attack) * invasion attack buff

Regular attack buffs include crux amplifier, crimson amplifier, crimson obelisk, and ancient crystal foci
The only invasion attack buff that I can think of right now is the Atmospheric Decimator
Note that the invasion attack buff modifies the complete total, not just the invasion-only portion... according to Dan
Also, when there are multiple buffs remember they are multiplied together (as opposed to some games where they'd be added together)

Eh, not exactly. Remric is right in that only Dan knows.
For me to be right the invasion attack equation would work similar to this, ((Attack*Attack Mulipler)+(Invasion Attack*Invasion Attack Multiplier))=Total Invasion Attack
For you to be right it would be similar to this, (((Attack+Invasion Attack)*Attack Multiplier)*Invasion Attack Multiplier)=Total Invasion Attack
We could test this, but It would be hard and somewhat stupid to do.

EDIT: Taking Lone's info into consideration I cant be right, but weather its Lone's equation or ((Attack+Invasion Attack)*Attack Multiplier)*Invasion Attack Multiplier)=Total Invasion Attack still could be tested.