What is the average rate of change for this function for the interval from x=1 to x=3

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?

Ihave trouble finding the nth term of a linear sequence

What is the solution set of the quadratic inequality x^2-5< or equal to 0