How do you solve x^2 + 2x-7=0?

1 Answer
Apr 19, 2016

x = -1 pm 2sqrt{2}

Explanation:

Use the quadratic formula for this question where you can't find a master product that will have factors that add to the b term.

Quadratic Formula
x = (-(b) pm sqrt{b^2 - 4ac})/(2a)

Substitute the values into its corresponding places and evaluate.
x = (-(2) pm sqrt{2^2 - 4(1)(-7)})/(2(1))
x = (-2 pm sqrt{4 + 28})/(2)
x = (-2 pm sqrt{32})/(2)
x = (-2 pm 4sqrt{2})/(2)

Simplify the terms (other than the 2 inside of the radical sign) by diving them by the common factor of 2.
x = (-1 pm 2sqrt{2})/(1)

Answer: x = -1 pm 2sqrt{2}