Use the objective function p  =  50x  +  80y to calculate the profit at each point

I have attached a screenshot with the question.

Now, we are given the function:
P = 50x + 80y

From the given graph, we can define the three points at which we want to get the profit.
These points are:
(0,5) , (1,12) and (4,10)

At (0,5):
we have x = 0 and y = 5. Therefore:
P = 50x + 80y
P = 50(0) + 80(5)
P = 400

At (1,12):
we have x = 1 and y = 12. Therefore:
P = 50x + 80y
P = 50(1) + 80(12)
P = 1010

At (4,10):
we have x = 4 and y = 10. Therefore:
P = 50x + 80y
P = 50(4) + 80(10)
P = 1000

Hope this helps :)