First, think of the remote interior angle theorem. So basically the remote interior angles that don't share a vertex with the exterior angle is the sum of the exterior angle. So that means ∠EBC+∠BEC=∠ECD. ∠ECD=64 degrees+90 degrees=154 degrees. ∠EBC is equal to 180 degrees minus 3x because line AD is a line so ∠ABE and ∠EBC are supplementary angles so basically they add up to 180 degrees. So the equation is (180-3x)+x=154. Simplify the equation and you should get x=13 degrees:)
