How do you solve $x² = 2x + 4$ using the quadratic formula?

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Answer 1 · 2015-10-17T12:54:52

-1.236, 3.326

Rearrange the formula so all the terms are on one side of the equals sign. (Subtract 2x and 4 from both sides)
$x^2 - 2x - 4 = 0$

The Quadratic Equation is based on the formula form of $y = ax^2 + bx + c$ , so now a = 2, b = -2, and c = -4

Substitute these variables into the Quadratic Equation, $x =( (- b - sqrt (b^2 - 4ac)) / (2a))$ , $((-b + sqrt(b^2 - 4ac))/(2a))$

$x = (- -2 -sqrt((-2)^2 - 4*1*-4))/(2*1)$

$x = (2-sqrt(4+16))/2 = (2-sqrt(20))/2 = (2-4.472)/2$ and

$x = (2+sqrt(4+16))/2 = (2+sqrt(20))/2 = (2+4.472)/2$

$x = -2.472/2 , 6.472/2$

How do you solve x² = 2x + 4x² = 2x + 4 using the quadratic formula?