Answer:
140, 60
Explanation:
15x+5 + < CDB =180 line form an 180 angle
180-80-6x-6 = < CDB sum of angles in a triangle is 180
substitute < CDB from second to first
15x+5+180 -80-6x-6 =180
combine like terms
9x -81 =0
x=81/9=9
so angle YDC = 15*9+5 = 140 degrees
and angle DBC = 6*9+6= 60 degrees