I am taking pre-cal at our local college and have my final on monday. The teacher gave us a study guide but I am having a few problems and need some help please. I am stuck on these two problems:

solve algebraically between [0,2pie]

2cosx +Sq. root2=0

other problem: solve for x

arccos x- arccot6/5=0

Can someone please show me how to work these. I am sure we went over it in class but I am lost. Thank you