SOLUTION: A truck that can carry no more than 6800 lb is being used to transport refrigerators and upright pianos. Each refrigerator weighs 300 lb and each piano weighs 525 lb. Write and gra

Let x = the number of refrigerators
Let y = the number of upright pianos



We graph the boundary line:



Divide through by 25 to simplify:



The intercepts are  and 

We draw the boundary line, and shade below it because the
origin used as a test point:


 

gives a true inequality



Will 10 refrigerators and 9 pianos overload the truck?

The points inside or on the boundary of the shaded region
represent the loads the truck can carry.  The x-coodinate
is the number of refrigerators, and the y-coordinate is
the number of pianos.

We plot the point (10,9) and see if it is in the shaded region:



The point (10,9) is outside the shaded region, so yes,
10 refrigerators and 9 pianos will overload the truck.

Edwin