SOLUTION: Solve the equation x^2 + 8x - 2 = 0 using both the quadratic formula and completing the square method.

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Question 201740: Solve the equation x^2 + 8x - 2 = 0 using both the quadratic formula and completing the square method.
Answer by Alan3354(5863) About Me  (Show Source):
You can put this solution on YOUR website!
Solve the equation x^2 + 8x - 2 = 0 using both the quadratic formula and completing the square method.
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Complete the square:
x^2 + 8x - 2 = 0
x^2 + 8x = 2
x^2 + 8x + 16 = 18
(x+4)^2 = 18
x+4 = +/-sqrt(18)
x = -4 +/- 3sqrt(2)
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Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=72 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 0.242640687119285, -8.24264068711928. Here's your graph: