Question

As raízes da equação (x + 2)2 = 9, são:
(A) -3 e 3
(B) -1 e 1
(C) 1e-5
(D) 7 e-11

Answer 1

(x + 2)² = 9

(x + 2) = √9

(x + 2) = ±3

=> x+2 = +3 => x' = 3-2= 1 ✓

=> x+2 = -3 => x" = -3-2= -5 ✓

====> (C) 1e-5

ou:

x²+4x+4=9

x²+4x-5=0

∆=16+20=36 => √∆=6

x= -b±√∆/2.a

x= -4±6/2

x'=-4+6/2=2/2=1

x"=-4-6/2=-10/2=-5