How do you solve $x^2-2x-4=0$ by completing the square?

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How do you solve $x^2-2x-4=0$ by completing the square?

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Answer 1 · 2018-03-03T08:08:36

$color(purple)(x = sqrt5 + 1, -sqrt5 + 1 = 3.236, -1.236$

Explanation:

$x^2 - 2x - 4 = 0$

$x^2 -2x = 4$

Add 1 to both sides,

$x^2 - 2x + 1 = 4 + 1 = 5$

$(x-1)^2 = (sqrt5)^2$

$x-1 = +- sqrt5$

$color(purple)(x = sqrt5 + 1, -sqrt5 + 1 = 3.236, -1.236$

Answer 2 · 2018-03-03T08:22:27

$x=1+-sqrt5$

Explanation:

$"using the method of "color(blue)"completing the square"$

$• " the coefficient of the "x^2" term must be 1 which it is"$

$• " add/subtract "(1/2"coefficient of x-term")^2" to"$
$x^2-2x$

$rArrx^2+2(-1)xcolor(red)(+1)color(red)(-1)-4=0$

$rArr(x-1)^2-5=0larrcolor(blue)"add 5 to both sides"$

$rArr(x-1)^2=5$

$color(blue)"Take square root of both sides"$

$rArrx-1=+-sqrt5larrcolor(blue)"note plus or minus"$

$"add 1 to both sides"$

$rArrx=1+-sqrt5larrcolor(red)"exact solutions"$

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How do you solve $x^2-2x-4=0$ by completing the square?

2 Answers

Explanation:

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Science

Math

Humanities

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How do you solve x^2-2x-4=0 x^2-2x-4=0 by completing the square?

2 Answers

Explanation:

Explanation:

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How do you solve $x^2-2x-4=0$ by completing the square?