21 and -4, because -4x21 = -84, and 21+-4 (– 4) = 17
Answer:
There will be 213 songs in each group.
Step-by-step explanation:
Suppose, the number of songs in each group is 
As he has 4 different groups of songs, so the t<u>otal number of songs in all 4 groups</u> will be: 
Given that, the mp3 player has a <u>total of 852 songs</u>. So, the equation will be........

So, there will be 213 songs in each group.
The answer would be x=14/3 and x=-28/3. Hope this helps!