Respuesta :

x^2 + 9x + 20 = 0
(x + 4)(x + 5) = 0
x + 4 = 0 or x + 5 = 0
x = -4 or x = -5
x = -5, x = -4

Answer:

The correct option is 3.

Step-by-step explanation:

The given equation is

[tex]x^2+9x+20=0[/tex]

Factorize the given equation.

[tex]x^2+5x+4x+20=0[/tex]

[tex]x(x+5)+4(x+5)=0[/tex]

[tex](x+5)(x+4)=0[/tex]

Equate each factor equal to zero.

[tex]x+5=0\Rightarrow x=-5[/tex]

[tex]x+4=0\Rightarrow x=-4[/tex]

The solutions of the given equation are x=-5 and x=-4. Therefore the correct option is 3.