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!