Question 947328
1.) Michael travels x miles, so Michael =x  Rachel travels 15 more than Michael so her equation would be R=m+15

You have to add 15 miles to Michael (x) to get Rachel's.

2.)
We still have the same equations for Michael and Rachel. 
Michael = X 
And
Rachel = (X + 15)


(I use the parenthesis because it is easier to distinguish who is who)

If Daniel travels three times as many miles as Rachel, then his equation would be 
3(X + 15)


I hope this helps!

This is because Rachel is the amount in the parenthesis and Daniel travels three times as many miles.