Robert

The D.E you mentioned is not separable ....it has the type dy/dx+a(x)y=b(x)

where a(x) and b(x) are functions of x. This type of D.E is linear D.E first order...and cannot be solved by separating the variables...

consult your book about the linear D.E of first order and see how you can solve it ....IT IS EASY.

MINOAS