What is n-6 divided by n to the power of 3 minus 15n to the power of 2 plus 45n plus 63

Can someone me my sister? she is in third grade. 50 points and brainlist! ones that are not answered. plz and thx!

Simplify the expression. -2/5(10+15m-20n)

At the olympic games, many events have several rounds of competition. one of these events is the men's 100-meter backstroke. the upper dot plot shows the times (in seconds) of the top 8 finishers in the final round of the 2012 olympics. the lower dot plot shows the times of the same 8 swimmers, but in the semifinal round. which pieces of information can be gathered from these dot plots? (remember that lower swim times are faster.) choose all answers that apply: a: the swimmers had faster times on average in the final round. b: the times in the final round vary noticeably more than the times in the semifinal round. c: none of the above.