Respuesta :

Astute
Hey there,

By using the [tex]AC[/tex] method . . . 

[tex] x^{2} +bx+c[/tex]

We do [tex] (a^{2} -a-20)[/tex] using the 
[tex]AC[/tex] method, and from this, our
answer would give us . . . 


[tex](a-5) \ (a+4)[/tex]

Hope this helps.
~Jurgen