Solve the following using separation of variables. Let C represent an arbitrary constant.

1) (11 + x^2)y ' = 11x^(3)*y

^ I got (Ce^((11x^2)/2))/(e^(11log(x^2+11))) but that's not correct.

Solve the initial value problem.

2) y ' - 2y + 4 = 0, y(1) = 12

^I don't even know how to approach this one.

3)y^2 * dy/dx = x^(-3), y(5) = 0

^I got ((25-x)/6)^(1/3) but that's wrong.

I'm not necessarily looking for the answers...but take me step my step? Or atleast guide me through one or two of them?

Thanks ahead of time!