Tony believes that x = - 9 is a root of the polynomial x2 + 13x + 36. Erika, however, believes that x = 4 is a root of the same polynomial. Who is correct?

Multiply 36 and x together in such a way that the multiples add up to 13.

36x

9 and 4 add to 13

Divide and 4 by x.

(x + 9) (x + 4)

Set to zero.

(x + 9) (x + 4) = 0

x = - 9

x = - 4

Based on above, it is determined that Tony is correct.

Answer:

x = - 9, Tony's assumption is correct.