If you mean you connected the jumper cables around the wrong way then you may have blown the amp in the stereo. Speakers shouldn't be affected.
I've never tried that, but I am pretty sure the battery would no longer work.
it dont last longer.
energysetr
yes it does i have done a experiment and energizer last longer that duracell
I think diz nuts last longer
Dead battery -will no longer charge.
the battery will no longer work.
NO they do not last longer
See this link.
ENERGIZER
Aa energizer
energizer