SOLUTION: Solve by completing the square x^2 + 8x = 5

Question 247234: Solve by completing the square
x^2 + 8x = 5
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
take (8/2)^2
4^2=16
add 16 to both sides
x^2 + 8x +16= 21
(x-4)^2=21
get sqrt
x=+\-sqrt(21)
other methods of solving

Solved by pluggable solver: SOLVE quadratic equation with variable

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=84 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 0.58257569495584, -8.58257569495584. Here's your graph:

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