What is the maximum value of 4(x+7)(2-x), over all real numbers x?
If we graph this out, we can see that the maximum for 4(x+7)(2-x) would be 81, for x = -5/2.
You can figure out x=-5/2
using the formula -b/2a
But first you have to expand
then graph the quadratic
+321 
+2862 
