What are the roots of the polynomial equation?

x^2 + x -72 =0

There are many ways you can go. I'm going to start out factoring the whole thing.
(x+9)(x-8) = 0
seperate these into two different equations.
x+9 = 0     and       x-8 = 0
x= -9                      x=8
 Make sure you check it by substituting. Sometimes you might have to reject an answer. In this case you don't. Therefore, 8 and -9 are your roots!