How do you solve this completing the square: x2 + 6x + 1 = 0?

Question

How do you solve this completing the square: x2 + 6x + 1 = 0?

Answer 1

x^2 + 6x + 1 = 0 (subtract the constant, which is 1, from both sides)

x^2 + 6x = -1 (take half of the x-term 6x, which is 3, and square it to 9; add this to both sides)

x^2 + 6x + 9 = -1 + 9 (factor on left side and add on right side)

(x + 3)^2 = 8 (square root both sides)

x + 3 = sqrt8 or x + 3 = -sqrt8

x = sqrt8 - 3 or x = -sqrt8 - 3 <===ANSWER

How to solve quadratic equations by completing the square: http://www.purplemath.com/modules/sqrqua...

Answer 2

x^2+6x+9=-1+9

(x+3)^2=8

x+3=(+ or -)sqrt(8)

x=-3+sqrt(8)

x=-3-sqrt(8)

Answer 3

Look here

http://www.purplemath.com/modules/sqrqua...

there's a nice little animated example halfway down the page which will teach you the correct method, as opposed to just filling in the answer for you, it's very easy to follow

Answer 4

(I trust you know a bit about completing the square beforehand)

So basically you want (x+something)^2 + something-x. (if that makes sense)

Well the only thing that you can really do first is (x+1)^2 because that is the only thing satisfying x^2 and 1 and then the answer would be x^2 + 2x + 1. We want 6x instead of 2x so add the 4x on after:

(x+1)^2 + 4x

That is how you complete the square then...

Well I hope that helped   =]

Answer 5

By reading the math book and paying attention in class instead of posting this c**p on yahoo.answers.

Answer 6

What's the matter Nadia can't sleep, so trying to keep the rest of us awake? Sorry but this is so boring you're sending me to sleep. How many sheep was that??

Answer 7

x2 + 6x+1=0

X2+6X+9-9+1=0

(X+3)2-9+1=0

(X+3)2-8=0

(X+3)2=8

X+3=+_ SQUARE ROOT OF 8

X+3=_+ 2.828

X=-3+2.828 or -3-2.828

x=-1.828 or -5.828

Answer 8

x^2 + 6x + 1 = 0

x^2 + 6x = -1

x^2 + 6x + 9 = -1 + 9

(x + 3)^2 = 8

x + 3 = sqrt8

x = plus or minus sqrt8 - 3

Answer 9

take the square 10 2x 20 x6 140 add 1 141 conclusion 0.141