One way to do this is use the fact that the exterior angles of all polygons add up to 360 degrees
So an exterior angle of a regular octagon = 360 / 8 = 45 degrees.
So each interior angle = 180 - 45 = 135 degrees
so total measure of all angles in octagon = 8 * 135 = 1080 degrees
You haven’t showed us the picture
Always get rid of denominators first. Multiply both right and left side by 6
-7 (6) = -c (6)/6 + 12(6)
-42 = -c + 72
c = 72 +42
c = 114
rearrange like terms together
42 = 18 - 4x
4x = 18 -42
4x = -24
divide both sides by 4
x = -6
The answer is 21 - 17, which = 4.
Or you could +4 to CM (17) which equals CQ (21)
x = -9 and x = 8 when y = 0 is the answer
