Question 760485
2cos2x = 4cosx - 3
2(2cos^2x - 1) = 4cosx - 3
4cos^2x - 2 = 4cosx - 3
4cos^2 x - 4cosx + 1 = 0
(2cosx - 1)(2cosx - 1) = 0
 2cosx - 1 = 0
 2cosx = 1
  cosx = 1/2
     x = 60 degs and 300 degs
Hope this helps.
:-)