well you do the first one like this:

8.2 tan 2x = 10 0<x<180

divide the 8.2 to the other side

tan 2x = 10/8.2

take the inverse of tangent which makes it

tan^-1 (10/8.2) = 2x

divide the two so your left with x

and solve with a graphing calculator

[tan^-1 (10/8.2)]/ 2 = x = 25.324

then you can check 8.2*tan(2*25.324) = 9.999999 close enough haha

hope that atleast gets you on the right track