Exegesis:

mē echei charin tō doulō ‘is he grateful to the servant?’ mē presupposes an answer in the negative. echei has the same subject as erei in vv. 7 and 8. charin echō lit. ‘to give thanks’ means ‘to thank,’ ‘to be thankful.’

hoti epoiēsen ta diatachthenta ‘because he has done what was ordered,’ i.e. ‘what he was told to do.’

Translation:

Does he thank the servant? or, ‘he will not thank the servant’; or with further shifts, “the servant does not deserve thanks…, does he?” (Good News Translation). For to thank cf. on “ungrateful” in 6.35.

He did what was commanded, or, ‘he (i.e. the servant) did as he (i.e. the master) had commanded him, or, told him to do.’ One or both pronouns may require specification.

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.