Can you fix it? Fix it. Can't? Then why complain?

The source

"Can you fix it? Fix it. Can't? Then why complain?" Marcus Aurelius said it in Meditations 8.17. Translated by George Long, 1862.

"if thou canst, correct that which is the cause ... but if thou canst not do even this, of what use is it to thee to find fault?"

George Long, 1862, Meditations 8.17.

Who said it

Marcus Aurelius (121–180 AD). Roman emperor who wrote private notes to himself on a military campaign. We know them as the Meditations.

Questions

Who said "Can you fix it? Fix it. Can't? Then why complain?"?

Marcus Aurelius (121–180 AD). Source: Meditations 8.17.

What is the original wording?

if thou canst, correct that which is the cause ... but if thou canst not do even this, of what use is it to thee to find fault? (George Long, 1862). Translated by George Long, 1862.