First DB is a chord.
Line AC divide the chord DB into two equal length.
Hence
DE = EB
11x - 33 = 8x + 9
Collect like terms
11x - 8x = 9 + 33
3x = 42
x = 42/3
x = 14
Arc of AD
A circle is 360 degrees. Line AC divide circle into two semi circles. Hence, angle of a semi circle is 180 degrees.
Arc AD = 180 - 58 = 122