The second constraint is the same as the objective function, so your problem boils down to finding integer solutions to
.. 3x1 +5x2 = 36
There are 3 solutions. They are (x1, x2) = (12, 0), (7, 3), (2, 6)
The value of the objective function there is (obviously) 36.
The answer is going to be around 7 countries
It should open up because the a which is 4 is positive
7.779955 × 10 to the 4th power.
The answer is 4 So yeaaaa....