Answer:
x= 10°
Step-by-step explanation:
∡BDC +∡BCD= ∡CBS (ext. ∡= sum of int. opp. ∡s)
80° + 4x-5° = 15° +10x
80° -5° -15°= 10x -4x
60° = 6x
6x =60°
x= 60° ÷6
