Question 727196
If x = # of sweatshirts sold and y = # of T-shirts sold then the three inequalities should be


x+y ≥ 30
x+y ≤ 120
y ≥ 2x

Then you must add on x ≥ 0 and y ≥ 0 to make sure that you don't sell a negative number of either.


So in total, you'll have these 5 inequalities

x+y ≥ 30
x+y ≤ 120
y ≥ 2x
x ≥ 0
y ≥ 0



Now you graph each inequality (let me know if you need help doing this) and shade the appropriate region. The final solution set region will be the region where ALL of the inequalities overlap. This region is shown below


<img src="http://i150.photobucket.com/albums/s91/jim_thompson5910/Algebra%20dot%20com/graph1-4_zps8585f117.png">


Note: the pieces of the blue lines that are not touching the red shaded region are not part of the solution set, they are just part of the boundary lines


If you were to erase all of the parts of the lines that aren't in the solution region, then you would get something like this


<img src="http://i150.photobucket.com/albums/s91/jim_thompson5910/Algebra%20dot%20com/graph2-4_zps00678110.png">


That graph above is a better picture of the red solution region and the solid blue lines that make up the border of the solution region are also part of the solution set.


Basically if a point lies in that region or on the boundary, then it's a solution to all 5 inequalities that make up the system.