3520:20 should be correct
The rate of change is -6 because it’s being subtracted by 6 each time.
The distance between the points is 16
A quadrilateral, has 4 sides and its internal angles sum, add up to 360, now... you have 3 angles give.. .but we don't have C
so.. C is the difference of all the three angles from 360 or

whatever that is, now, you'll get some value in x-terms
so.... now once we know what C is
you can if you want, do a search in google for "inscribed quadrilateral conjecture", I can do a quick proof if you need one
but in short, for a quadrilateral inscribed in a circle, each pair of opposites angles are "supplementary angles", namely they add up to 180°
so.. what the dickens does all that mean? well D+B=180 and A+C = 180
now. we know what A is, 2x+1
and by now, you'd know what C is from 360-x-2x-1-148
so... add them together then and

solve for "x"
Answer:
First let's define what modular arithmetic is, what would come is an arithmetic system for equivalence classes of whole numbers called congruence classes.
Now, the modular division is the division in modular arithmetic.
Answering the question, a modular division problem like ordinary arithmetic is not used, division by 0 is undefined. For example, 6/0 is not allowed. In modular arithmetic, not only 6/0 is not allowed, but 6/12 under module 6 is also not allowed. The reason is that 12 is congruent with 0 when the module is 6.