Question

resolva por trinomio quadrado perfeito

a) x²+6x+9=0
b) x²+8x+16=36
c) x²+8x-9=0

Answer 1

x² + 6x + 9 = 0
x² + 3x + 3x + 9 = 0
x(x + 3) + 3(x + 3) = 0
(x + 3).(x + 3) = 0

x + 3 = 0
x = - 3

R.: x = - 3
*************************************
Báscara:
a = 1; b = 6; c = 9

Δ = b² - 4ac
Δ = 36 - 4.1.9
Δ = 36 -36
Δ = 0

x = - 6 = - 3
       2
**************************************
b)
x² + 8x + 16 = 36
x² + 8x + 16 - 36 = 0
x² + 8x - 20 = 0
(x + 10).(x - 2) = 0

x + 10 = 0
x = - 10

x - 2 = 0
x = 2

R.: x = 2 e x = - 10
--------------------------------------
c)

x² + 8x - 9 = 0
(x - 1).(x + 9)

x - 1 = 0
x = 1

x + 9 = 0
x = - 9

R.: x = 1 e x = - 9