How many times longer is 3/4 than 2/15

I'm terrible at math any here is appreciated.

Problem melissa is her dad build a walkway in their backyard. the walkway will be 54 feet long and 1.5 feet wide. the local hardware store sells tiles which are 1.5 by 1.5 feet and come in boxes of 12. how many boxes of tiles do they need?

Lindsay used two points, (x,y; ) and (+2.82), to find the equation of the line, y = mx + b, that passes through the points. y2-y, first, she used the definition of slope and determined that the value of mis x, - . given this information, which expression must represent the value of b?