Then I'll definitely will ask you questions about maths :)
Material=wall+2*side and material is 40 ft so:
40=w+2s
w=40-2s
Area=ws, using w from above we get:
A=(40-2s)s
A=40s-2s^2
dA/ds=40-4s and d2A/ds2=-4
Since d2A/ds2 is a constant negative acceleration, when dA/ds=0, A(s) is at an absolute maximum.
dA/ds=0 when 4s=40, s=10 ft
And since w=40-2s, w=20 ft
So the dimensions of the pen are 20 ft by 10 ft, with the 20 ft side being opposite the wall. And the maximum possible area is thus 200 ft^2
14 because - 11-17=-28. If you divide -28 by -2x you get 14
