Question

Which choices are solutions to the following equations x^2+8x-2=18

Answer 1

Answer:

-4 ± 2√6

Step-by-step explanation:

Rewritten in standard quadratic form, x^2+8x-2=18 becomes x^2 + 8x - 20 = 0.

Here the quadratic coefficients are a = 1, b = 8 and c = -20 and so the discriminant is b^2 - 4ac, or 8^2 - 4(1)(-20), or 96.

Because the discriminant is positive, we know that this quadratic has two different real roots.  These roots are:

      -b ± √(b² - 4ac)

x = -------------------------

                 2a

which in this case comes out to:

       -8 ± √96          -8 ± 4√6          

x = ------------------ = ------------------- = -4 ± 2√6

             2                        2