Do Your Best
Hang In There, Good Luck
expression
Remember 頑張る means “to persevere” or “to do one’s best”? This time you're telling someone to 頑張る, so this word means something like do your best, hang in there, or good luck! Speaking of which, 頑張れ, you!
The reading comes from 頑張る.
まあ、結果を気にせずに、頑張れよ！
Well, don’t worry about the results, just try your best!