Help please will give brainllst to the right answer

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?

What is the missing step in this proof ?

Solve 3x-18=2y and 5x-6y=14 by elimination or substitution . show all !