3r+n^2-r+5n= write in simplest form.

This equation in simplest form would be n^2+5n+2r

To get this you would do so:
3r+n^2-r+5n
3r-r+n^2+5n   REARRANGE so it is easier to simplify
2r+n^2+5n    SUBTRACT the r from 3r

n^2+5n+2r  REARRANGE again so it is in the correct order (numerical + alphabetical order) 

One shot. if 60% of 10 is 6, then what is 70%? we know it would be seven (since 60% is mathematically 60/100, or 6/10, then 70% is 70/100, or 7/10) but we can check anyway using ratios: 6 : 60% = x : 70%*inverse multiplicationx * 60% = 6 * 70%*divide both sides by 60%x = (6 * 70%) / 60%x = 7and since he has made 6 shots already, he would need just one more to get 7 shots or 70%. if the explanation is too confusing, comment and i will try to