No link or bot that it

Which point is on the line y=-2+3? (-2,-1) (3,3) (3,-3) (-3,-9)

I'm confused on this could anyone me and show me what i need to do to solve it.

The floor of a building consists of 3000 tiles which are rhombus shaped and each of it's diagonals are 45 cm and 30 cm in length. find the total cost of polishing the floor, if the cost per m² is rs. 4.