Answer:
800
Step-by-step explanation:
The objective here is to determine the socially optimal production of X.
For this to occur ; it is crucial that both firm must merge together.
Therefore; the Profit will be = Total revenue - Total Cost
From the question; the total revenue = 6X + 5Y ; &
The total cost is :

Now: The profit =

=

If the socially optimal production of X is the differential of the equation

(X) =

=

=

= 800
Thus the social optimal production of X = 800