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Jeans123
Group Title
Solve the quadratic equation by completing the square
x^212+7=0
 one year ago
 one year ago
Jeans123 Group Title
Solve the quadratic equation by completing the square x^212+7=0
 one year ago
 one year ago

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phi Group TitleBest ResponseYou've already chosen the best response.0
if you have time, this might help http://www.khanacademy.org/math/algebra/quadtratics/v/completingthesquare2
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
Humm. Quadratic... factor? complete the square? or quadratic formula?
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
Ah ha!! instructions say "completing the square", so I guess we'll completing the square :)
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
BTW... was the problem x^212x+7=0 (original was missing the x on the 12)
 one year ago

Jeans123 Group TitleBest ResponseYou've already chosen the best response.2
oops yes:)
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
cool. x^2 12x + 7 = 0 step 1: move the constant over x^212x= 7
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
step 2: take half the bx term \(12 \div 2 = 6\)
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
step 3: square the number in step # \(6^2 = 36\)
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
step 4: add the number from step 3 to both sides: \[x^2 + 12x + 36 = 7 + 36\]
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
so far so good?
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
\[x^2 + 12x + 7 = 0\] \[x^2 + 12x = 7\] \[x^2 + 12x + 36 = 7+36\] step 5: factor the lefthand side, and simplify the righthand side: \[(x+6)^2 = 29\] Hint  the lefthand side always factors to (x + # from step 2, including the sign, either + or )^2
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
from this point, use the square root property to finish solving for x.
 one year ago

Jeans123 Group TitleBest ResponseYou've already chosen the best response.2
x^2+12x+7=0?
 one year ago

Jeans123 Group TitleBest ResponseYou've already chosen the best response.2
that is what I started with?
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
did you just FOIL (x+6)^2 and subtract 29 to zero out the equation! Yep, that is back to where you started... :)
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
"Square Root Property" means take the square root \(\sqrt{\;\;\;}\) of both sides .
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
\[\sqrt{(x+6)^2} = \pm \sqrt {29}\]
 one year ago

Jeans123 Group TitleBest ResponseYou've already chosen the best response.2
I got x=+ .6148
 one year ago

cruffo Group TitleBest ResponseYou've already chosen the best response.1
\[\sqrt{(x+6)^2} = \pm \sqrt {29}\] humm.. \(\sqrt{29}\) does not simplify (other than decimal approx) so I'm gonna leave it for now... \[x+6 = \pm \sqrt{29}\] subtract 6 from both sides (but not from 29, that's inside the square root) \[x = 6 \pm \sqrt{29}\] that gives us two solutions: \[x = 6 + \sqrt{29} \approx 0.615\] and \[x = 6  \sqrt{29} \approx 11.385 \]
 one year ago

Jeans123 Group TitleBest ResponseYou've already chosen the best response.2
Thank you sooo much!!!!!:D
 one year ago
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