Respuesta :
Answer:
x = -2 ±2sqrt(2)
Step-by-step explanation:
x² + 4x + 4 = 8
Lets solve by completing the square
The left is set for completing the square since (4/2)^2 =4 so we rewrite this as (x+4/2)^2
(x+2) ^2 = 8
Take the square root of each side
sqrt((x+2) ^2 ) = ±sqrt(8)
x+2 =±sqrt(4*2)
x+2 =±sqrt(4)sqrt(2)
x+2 = ±2sqrt(2)
Subtract 2 from each side
x+2-2 = -2 ±2sqrt(2)
x = -2 ±2sqrt(2)
Steps to solve:
x² + 4x + 4 = 8
~Subtract 8 to both sides
x² + 4x + 4 - 8 = 8 - 8
~Simplify
x² + 4x - 4 = 0
This is in standard form [ ax² + bx + c ], so we can find the a, b, and c values.
a = 1
b = 4
c = -4
Use the quadratic formula [ [tex]x=\frac{-b+-\sqrt{b^2+4ac} }{2a}[/tex] ] to solve.
[tex]x = \frac{-4+-\sqrt{(4)^2-4(1)(-4)} }{2(1)}[/tex]
[tex]x = \frac{-4+-\sqrt{32} }{2}[/tex]
[tex]x = -2+-2\sqrt{2}[/tex]
Therefore, the correct answer is x = −2 ± 2√2 (Option A)
Best of Luck!