To answer this question, you need to see if the ordered pair solves both equations. If it is a solution to both, and only to both, then it solves the system. If it doesn't work in either one, it is not a solution. So, find out if:
2(5) + 6(-4) = -12 and if 2(5) = (-4) = 6.
If both are yes, then it is the solution. Otherwise, it isn't.