A 5.0 kg object is at rest with to forces applied to it, and a frictional force holding it in place. The two applied forces are: 15.0 N [x 60degrees y] and 12.0 N [x 215degrees y]. what is the coefficient of statics friction
Since the object is not moving, the friction force is the equilibrant (the reverse of the resultant) of the two applied forces.
This will only permit you to obtain a lower bound to the static friction coefficient. It is possible that a greater force could be applied without the object moving.
Whoever assigned this problem to you should know that.