Make it into a simultaneous equation:
5p + 4e = 7.65
4p + 5e = 7.20
Use adding/subtracting formula
The cost of an eraser is $1.44
These are how the graphs will look, they are color coded so have a look at the equations first.
I believe the length of the rectangle is 17 ft and the width is 14
80 - 2p
You use the distributive property