The denominator is x^2-3x-4. Factor it to identify its roots x^2-3x-4 = (x-4)*(x+1). Now you see that the roots are 4 and -1. Hence, the domain is the set of all real numbers except of -1 and 4 (because division by zero is PROHIBITED). ANSWER. The domain is the set of all real numbers except of -1 and 4.