I’m a little confused

Solve by any method (graphing, substitution or linear combination)y = x - 82x + 3y = 1a) (2, -6)b) (5, -3)c) (4, -4)d) (0, -8)i figured it out. the answer is (5, -3)

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle

Kelli swam upstream for some distance in a hour.she then swam downstream the same river for the same distance in only 6 minutes.if the river flows at 5km/hr, how fast can kelli swim in still water?