The correct answer is -b+12
The answer is -3.1111111111
First,you have to divide and see which number can go into 45 , 15 , and 30 what ever your answer is thats how many of each item you can put on each shelf. In your case it would be 15
(1 - (-3))/(0 - 6)
(1 + 3)/(-6)
4/-6
-2/3