OK.....
1 the arc C all of the way around to A is 2 * (5x+2)
This same arc is equal to 360 - 87 - 39 Right? Can you do it now?
2 ARC YZ = 2 * 59 This plus the 75 degree arc = 2 * 59 + 75
THIS plus the 17x-20 arc = 360 degrees (the entire circle)
so 2 * 59 + 75 + 17x -20 = 360 Right? Need more?