2x+y>3 describes the low end, presuming that you have defined to mean the number of field goals and to mean the number of free throws. yet your best game was 15, so the values must also satisfy 2x+y
10 is not a multiple of 3 so no 6/10 is not multiples for 3/10 and 6 is not a mutiple of 10 so it can't be also the same with 6/30 although 6/30 is multiples for 3 but 6 is not a mutiple for 10.
The solution would be like this for this specific problem:


The correct sequence of operations when solving
negative one over five (x − 25) = 7 would be multiply each side by −5, and adding
25 to each side.
Theres not enough information to answer this for you,