45.
12/18 = 8/x <=> 2/3 = 8/x <=> x = (3*8)/2 = 12;
You can make an cb chart. so to equal -6 you need the numbers -7, 1. so now the equation is ( x - 7 )( x + 1 ). if you want to solve it set it equal to 0 and solve.
14*15 is 210 which his the entire area. now divide 210/20 you get 10.5 so you will need at least 11 bags
