Can someone help me with my math I don't understand it

  317°

Step-by-step explanation:

The total measure of the angles around the center of the circle is 360°. The sum of angles in each half (above AB or below AB) is half that, or 180°. So, the sum of angles below the line is 180°. We can use that fact to find x, then the measures of all of the angles.

  (7x +1)° +90° +(9x -7)° = 180°

  16x = 96 . . . . . divide by °, subtract 84

  x = 6 . . . . . . . . divide by 16

Then angle AOD is ...

  (7·6 +1)° = 43°

Short arc AD is 43°, so long arc ACD is 360° -43° = 317°.

  arc ACD = 317°

to rewrite a literal equation you may need to divide by a number, or by a variable.

hope i .