First, get the interior angle of the 114 by subtracting 114 from 180, and you should get 66. Next, add the two known interior angles of 66 and 64 to get 130. With the knowledge that the 3 interior of all triangles add up to 180, you should know that 3x-40 is equal to 180 -130, or 50. With 3x+40 = 50, start by subtracting 40 from both sides for 3x = 10. Finally, divide both sides by 3 to get x = 3 and 1/3
