What is the curve which passes through the point (1, 1) and whose slope is $${{2y} \over x}$$ ?

If $$x\,dy = y\,dx + {y^2}dy$$, y > 0 and y(1) = 1, then what is y($$-$$3) equal to ?

What is the order of the differential equation $${{dx} \over {dy}} + \int {y\,dx = {x^3}} $$ ?

Which one of the following differential equations represents the family of straight lines, which are at unit distance from the origin ?