Relax

Respuesta :

Answer:

-5

Step-by-step explanation:

x² - 4x - 45 = 0

(x - 9)(x + 5) = 0

x = 9 or -5

x² - 25 = 0

(x + 5)(x - 5) = 0

x = 5 or -5

-5 is a common factor between both of them