The magnitud of an electric field is given as:

For the charge 1 the magnitude is:

Now, since charge 1 is negative this means that this field points towards the charge, in this case to the left, then the electric field for charge one is:

For the charge 2 the magnitude is:

Now, since charge 2 is positive this means that this field points away from the charge, in this case to the left, then the electric field for charge two is:

Now, the total field on point P is the sum of both electric fields, then the total electri field on this point is:
