Assuming the dual-slot pcb won't block any important connections, yes. The only difference between a single slot and dual slot card is their size. Just make sure your SATA ports or USB headers won't be blocked and you should be good to go.
Now, the real question you should be asking is if your psu can handle it.
Hi i was just wondering if this graphics card(XFX HD-685X-ZCFC Radeon HD 6850) will fit into this motherboard(GIGABYTE GA-78LMT-S2P AMD 760), and also how can you know which side the dual slot will go on. I'm also a nooob