Answer:
2nd graph
Explanation:
You have the next restriction:
x*40 + y*75 <= 7500
where
x: number of boxes that weigh 40
y: number of boxes that weigh 75
Every point below the line fulfill the equation, for example, x = 1 and y = 1 is in the shaded region because 40 + 75 is less than 7500. The difference between dashed and solid line is that in the first case the line is not included in the solution and in the second it is. In this case the line is solid because the restriction has a less or equal sign (<=), for example, point x = 0 and y = 100 is less or equal to 7500 and fulfill the equation.