Answer:
math error ...............
If you simplify what's in the bracket, you get 3n
=(3n)+4=32/2
=3n+4= 32/2(here we can either crossmultiply or equate)
3n+4-4=32/2-4(subtract 4 from both sides)
3n=32/2-4
3n=24/2
3n=12
3n=12(divide both sides by the coefficient of the unknown)
3n/3=12/3
n=4
For this case we can propose a system of equations:
x: Let the variable that represents the number of small cookies
y: Let the variable that represents the number of large cookies
According to the statement we have:

We multiply the first equation by -2:

We have the following equivalent system:

We add the equations:

We look for the value of the variable "x":

Answer:
They sold 80 small cookies and 50 large cookies