How to connect speaker to my PC that have + and - at the back?

Hi.
I got these pair of old big speakers that dont have any thing but + and - in the back.
How can I connect them to my PC and leaving my 2 computer small speakers on too?

Thx

If the only connection/cable on the "old" speaker is a +/- speaker terminal, then you won't be able to use it with your computer -- at least not directly. It's been a long time since computer sound cards provided an amplified output. Typically, the speakers must be self amplifying, i.e. power is being supplied to at least one half of a pair (or to the included subwoofer of a three speaker set) and the second speaker is connected directly to the first speaker.

In order to use a non-amplified pair of speakers with the computer, you have to run the sound from the computer to an amplifier or audio receiver, and from there to the speaker(s).

i have this same problem, what a shame