$\displaystyle f(x,y)= y/x^2$

what is the domain and range?
describe the level curves, the boundary of the domain and determine if the domain is an open or closed or neither region.

Also what points (x,y) in the plane is this function continuous.

$\displaystyle g(x,y) = x^2+y^2/x^2-3x+2$

i dont really understand these questions at all. I dont really understand the range of 2 variable functions as well as the level curves all that well. For the second question im not real sure where to start.