I would say that if the ones add up to 10 or more, they will regroup and put a 1 above the tens column to show the 10
Explanation is given step by step just below:
tan(theta(t))=y(t)/x(t)
differentiate
sec^2(theta(t))*theta'(t)=y'(t)x(t)-y(t)x'(t)/x^2(t)
thus
theta'(t)=(y'(t)x(t)-y(t)x'(t))
divided by (x^2(t)*sec^2(θ(t))
-8x - 46 = -6x - 8
-8x + 6x = -8 + 46
-2x = 38
x = -19
The equation:
-8x - 46 = -6x - 8
The solution:
x = -19
∠DOC is the average of the given angle values,
(170° +44°)/2 = 107°
∠DOB is the supplement to that,
180° -107° = 73°
The appropriate choice is
B) 73°