Determine two coterminal angles (one positive and one negative) for the given angle. Give your answer in radians.

A) 8pi/9 B) 8pi/45

For 8pi/9 I added 18pi/9 which equals 26pi/9 - 18pi/9 = -10pi/9.

I do not know how to find the positive one for 8pi/9 and I do not know what to do for b.