Can anyone explain line graphs to me please

The standard distance between studs in a house is 1.5 feet. if you have a set of blueprints for a house that mark every 1.5 feet with 2 in., by how many inches will a 13-foot wall be represented?

Akitchen is 12 ft. by 14 ft. with 10 ft. high walls. how much would it cost to put vinyl flooring in this room? $8.80 per ft

Which shows the first equation written in slope-intercept form? 1/2 (2y + 10) = 7x