Respuesta :

Answer:

Step-by-step explanation:

z^2+9z+20

=z^2+(5+4)z+20

=z^2+5z+4z+20

=z(z+5)+4(z+5)

=(z+5)(z+4)

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z^2 + 9z + 20

z^2 + 5z + 4z+ 20

z(z + 5) + 4 (z+5)

(z+5) (z+4)