What do two equivalent expressions always have in common?

What is the equation in point slope form of the line that passes through the point (-1, -3) and has a slope of 4? y-1=4(x-3) or y+3=4(x+1)

Akitchen floor is made up of tiles that are in the shape of the triangle shown there are 40 tiles on the kitchen floor what is the total area of the floor

How can you tell when x and y are not directly proportional?