Question

( x + 3 )² = 25

fazendo favoooor!

Answer 1

(x + 3)² = 25
x² + 2 . x . 3 + 3² = 25
x² + 6x + 9 = 25
x² + 6x + 9 - 25 = 0
x² + 6x - 16 = 0
   a = 1; b = 6; c = -16
      x = [- b ± √(b² - 4ac)] / 2a
      x = [- 6 ± √(6² - 4 . 1 . [-16])] / 2 . 1
      x = [- 6 ± √(36 + 64)] / 2
      x = [- 6 ± √100] / 2
      x = [- 6 ± 10] / 2
      x' = [- 6 - 10] / 2 = -16 / 2 = -8
      x'' = [- 6 + 10] / 2 = 4 / 2 = 2

S = {-8, 2}

Espero ter ajudado. Valeu!

Answer 2

(x+3)^2=25
(x+3)(x+3)=25
x^2+3x+3x+9=25
x^2 +6x+9=25
x^2+6x+9-25=0
x^2+6x-16=0
6^2 -4.1.(-16)=delta
delta= 36- (-64)
delta=36+64
delta=100
x=-6+/- raiz de 100/2
x=-6+/-10/2
x1=-6+10/2
x1=4/2
x1=2
x2=-6-10/2
x2=-16/2
x2= -8
s={2,-8}