What is the solution of $$(1 + 2x)dy - (1 - 2y)dx = 0$$ ?

What are the order and degree, respectively, of the differential equation $$\left( {{{{d^3}y} \over {d{x^3}}}} \right) = {y^4} + {\left( {{{dy} \over {dx}}} \right)^5}$$ ?

What is the degree of the differential equation $${{{d^3}y} \over {d{x^3}}} + {\left( {{{dy} \over {dx}}} \right)^2} - {x^2}\left( {{{{d^4}y} \over {d{x^4}}}} \right) = 0$$ ?

Which one of the following is the differential equation that represents the family of curves $$y = {1 \over {2{x^2} - C}}$$,where C is an arbitrary constant?