Solve by factoring: x^2 - x - 72 = 0

[Stine]

Solve by factoring: x^2 - x - 72 = 0

I started by factoring it as: (x - 9)(x + 8) = 0

I am not sure where to go from here????? :?

 

[tkhunny]

If A*B = 0, what can you say about A or B?