i have 6.5 and 5.25 inch speakers and im wondering if i can just mount them in a door or i also have a headliner with little compartments im wondering if i should build little mdf enclosures in the doors and headliner or if i should just mount them in there and sound deaden it.

and no the answer is not -1 because you are squaring "X" and neg times neg is a positive. therefore is X=-1 then the equation is equal to 2 not 0