I'm trying to figure out how to connect my ASUS GTX670 graphics card. My power supply is a EVGA 760W GOLD. I have three cables 8/6+2 and the graphics card has two 6 pole input connectors. How do I connect? Should I use two cables and just use the 6-pole connector from each?

Yes, bend the 2 connectors out of the way.

Another problem arose.
The motherboard ASUS Prime B350-PLUS has a EATX12V 8-pole socket. The EVGA 760W GOLD PSU has three VGA cables. After feeding the graphics card using two of them I have one to spare. It's a 8/6+2 and it would fit but what about the cable's wiring. Is meant to be using for this or do I have get another cable?
 
I found a 2x4 cable marked CPU. Could it be used?