X - the number of loads by land carriers,
y - the number of loads by air carriers;
The system of inequalities:
x + y ≤ 150
2,000 x + 1,250 y ≤ 180,000
Positive 3, If You're starting at -6 and you add the first 6 it's at 0, now you have 3 more to add to make 9. And that gives you positive 3. or if you do 9 - 6 you can get your answer that way too.
......what's the question?