Differential equation is something which contains derivatives or differentials. A derivative or differential is the rate of change of one variable with respect to another.

The differential equation will be of the form
                                               y = f(x)

where y is the dependent variable  and x is the independent variable.

 Depending on the order of the derivative we can classify the differential equations into
  1. First order differential equation
  2. Second order differential equation
  3. Higher order differential equation.
Suppose you have any differential equation you can solve it by the following steps:
Step 1: Read the given problem and observe whether it is of the form y' = f(x),
where x and y are variables.

Step 2 : Separate out those two variables by taking x variable on one side and y variable on the other side.

Step 3 : Integrate on both the sides to get the differential equation.