Jin donated earning from 2 songs to charity. he donated 864 altogether jins second song earned 5 times much as his first song. how much money did jins second song earn

Since Jin donated his money to charity and he donated $864, that is our total. 
We don't know the first amount, so we can call it x. 
We don't know the second amount either, but we do know it was 5 times the first, so 5*x = 5x.
We first need to find how much Jin earned for the first song. We need to find x. 
x + 5x = 864, then combine like terms6x = 864, then divide both sides by 66x/6 = 864/4x = 144
The fist song made $144. But the second made 5 times that. So we just multiply 144 by 5. 144*5=720. 
The final answer is $720.