How do I solve by completing the square. Express the solutions in simplest radical form: 1/2x^2 + x - 13 = 0?

Question

anonymous · Answer

Easy to re-write it as:
x^2 + 2x - 26 = 0

Then, completing a square will give you:
x^2 + 2x + 1 - 27 = 0
(x+1)^2 = 27

anonymous · Answer

The answer is supposed to be $$-1 +/- 3\sqrt{3} $$

anonymous · Answer

'cause I got x = -1 +/- √105 / 4

anonymous · Answer

Well, when (x+1)^2 = 27, you do get:
x + 1 = +/- SQRT(27)
x + 1 = +/- 3*SQRT(3)
x = -1 + 3 * SQRT(3)
OR
x = -1 - 3 * SQRT(3)

radar · Answer

$$(x+1)^{2}=27$$$$(x+1) =\sqrt{27}$$$$x = -1 \pm \sqrt{27}$$$$x = -1\pm \sqrt{9}\sqrt{3}$$$$x=-1\pm3\sqrt{3}$$Do you see how GT answers is the same as your book's answer?