Question

x²+9x+20=0 Alguém resolve!

Answer 1

delta = 1
x'= 5
x"=4

delta=81 - 4 ( 1 ) (20)         
delta = 81 - 80                        
delta =1  
x'= 9 + 1   
 --------         = 5                 
 2 
x"= 9-1
     ----------  = 4
          2

Answer 2

a = 1 , b= 9, c= 20
delta = b² - 4ac
delta = 9² - 4*(1)*(20)
delta = 81 - 80
delta = 1

x = [- b +/- raiz(delta)] / 2a
x = [- 9 +/- raiz(1)] / 2*1
x = (-9 +/- 1) / 2
x' = (-9 + 1) / 2 => x' = -8 / 2 => x' = - 4
x" = (-9 - 1) / 2 => x" = -10 / 2 => x" = - 5