solve this differential equation!?

Question

In a third order chemical reaction the number of grams X of a compund obtained by combining 3 chemicals is governed by
dX/dt= k(a-X) (b-x) (c-x).
solve the DE under the assumption a,b,c are not equal

Answer 1

dx/[(a-x)*(b-x)*(c-x)] = k*dt

∫1/[(a-x)*(b-x)*(c-x)] dx = ∫k dt

Answer 2

Try separating the variables.