Angles EBA and DBC are congruent. The three angles EBA, EBD, and DBC are together supplementary, so their measures sum to 180°. This means
x + (4x + 11°) + x = 180°
6x + 11° = 180°
6x = 169°
x = (169/6)°
Then the measure of angle D is
2x + 8° = 2 (169/6)° + 8° = (193/3)°
The interior angles of any triangle sum to 180°, so if y is the measure of angle C, we have
(169/6)° + (193/3)° + y = 180°
y = (175/2)° = 87.5°
