Acer Extensa 5420, is it possible to use external speakers with this lap top?

If you hook speakers up to line in then you will hear nothing. If you use line out then you might hear something, but a line out signal is not amplified and would require at least a preamp. So if the speakers have no built-in preamp don't expect much. Keep in mind speakers attached to the headphone jack should be 8 ohms speakers