x*2 - 8x - 19 = 0. how do i use it with completing the square?

Question

any help is appreciated :)

Answer 1

Start with your equation:
x² - 8x - 19 = 0

Move the unit term to the right side:
x² - 8x = 19

To complete the square, take half the coefficient on the x-term (-4) and square it (16). Add this to both sides:
x² - 8x + 16 = 19 + 16

Now you can rewrite the left side as a perfect square:
(x - 4)² = 35

Take the square root of both sides:
x - 4 = +/-sqrt(35)

So you have two answers:
x - 4 = sqrt(35)
or
x - 4 = -sqrt(35)

Add 4 to both sides:
x = 4 + sqrt(35)
or
x = 4 - sqrt(35)

Answer 2

x^2 - 8x = 19
divide 8 by 2 and square that answer
(8/2)^2 = 16
x^2 - 8x + 16 = 19 + 16
(x + 4)^2 = 25

Answer 3

x² - 8x - 19 = 0
x² - 8x = 19
x² - 8x + 16 = 19 + 16 ........(16 is 8/2 squared)
(x - 4)² = 35
x - 4 = ±√35
x = 4 ± √35