Does anyone know the answer to that question?

is only a line? i think so

the function makes a strait line horizontally with no x intercept but a y intercept at 9.

it will cost dollar $540

the living room is 3 which means if we divide 325/3 then we get $108

therefore if 1part of the living room cost $108 and 3 costed $325

then total 5part of the room will cost 5*108 which gives $540