okendall
okendall okendall
  • 22-01-2020
  • Mathematics
contestada

2. Confirm that 1+V5 and 1 - V5 are the correct roots for x2 – 2x – 4 = 0.

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jimrgrant1 jimrgrant1
  • 22-01-2020

Answer:

see explanation

Step-by-step explanation:

Given

x² - 2x - 4 = 0 ( add 4 to both sides )

x² - 2x = 4

To solve use the method of completing the square

add ( half the coefficient of the x- term )² to both sides

x² + 2(- 1)x + 1 = 4 + 1

(x - 1)² = 5 ( take the square root of both sides )

x - 1 = ± [tex]\sqrt{5}[/tex] ( add 1 to both sides )

x = 1 ± [tex]\sqrt{5}[/tex], thus

x = 1 + [tex]\sqrt{5}[/tex] or x = 1 - [tex]\sqrt{5}[/tex]

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