As you haven't specified which angle is between which sides, let me assume that #alpha# is the angle that is opposite to #a#, #beta# is the angle opposite to #b# and #gamma# is the angle opposite to #c#.
With this assumption, you can use the law of sines to solve your problem:
#sin alpha / a = sin beta / b = sin gamma / c#
1) First, with #a#, #b# and #alpha# given, you can find #beta#:
#sin beta = sin alpha / a * b = sin 75^@ / 9 * 8#
#=> beta = arcsin ( sin 75^@ / 9 * 8) ~~ 59.16^@#
2) As next, you can determine #gamma# since #alpha + beta + gamma = 180^@# must hold in any triangle:
#gamma = 180^@ - alpha - beta = 180^@ - 75^@ - beta ~~ 45.84^@#
3) Finally, you can use the law of sines again to compute #c#:
#c = a / sin alpha * sin gamma ~~ 6.588#
