Respuesta :

choco4
to factor you have to do this: 

s^2 + 9s = -20
      + 20    +20

s^2 + 9s + 20 = 0

now you need to numbers that multiplied give you 20 
and then those same 2 numbers have to add to 9

5 x 4 = 20
5+ 4 = 9

(x + 4) (x+ 5)

that means that x= -4, and -5