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Mathematics 20 Online
OpenStudy (anonymous):

k

OpenStudy (anonymous):

are we solving for x here?

OpenStudy (solomonzelman):

\[\sqrt{x+7}-x=1\]Right?

OpenStudy (anonymous):

x will = 9

OpenStudy (anonymous):

It says solve and to check for extraneous solutions. And yes @SolomonZelman

OpenStudy (solomonzelman):

\[\sqrt{x+7}-x=1\]\[\sqrt{x+7}-x\color{red} { +x }=1\color{red} { +x }\]\[\sqrt{x+7}=x+1\]square both sides\[(~\sqrt{x+7}~)\color{red} { ^2 }=(~x+1~) \color{red} { ^2 }\]\[x+7=x^2+2x+1\]so far so good?

OpenStudy (anonymous):

Ahh okay. I'm following.

OpenStudy (solomonzelman):

\[x+7\color{red} { -x }=x^2+2x+1\color{red} { -x }\]\[7=x^2+2x+1\]\[7\color{red} { -7 }=x^2+2x+1\color{red} { -7 }\]\[x^2+2x-6=0\]what about now?

OpenStudy (anonymous):

Yes. It's a lot of steps, but it's helping me understand it better. What next??

OpenStudy (solomonzelman):

can you do it now?

OpenStudy (anonymous):

Well I'm not too sure. I had a few guesses what x was, but I don't think they're right. What would I do next? Sorry, I'm not too good at math.

OpenStudy (anonymous):

Do we factor?

OpenStudy (solomonzelman):

Sorry for not replying right away.

OpenStudy (anonymous):

It's okay. Gave me time to look into the problem more. :)

OpenStudy (solomonzelman):

\[\huge\color{blue}{ \frac{-b±\sqrt{b^2+4ac} }{2a} } \]

OpenStudy (solomonzelman):

\[\huge\color{blue}{ \huge\color{red}{1}x^2+\huge\color{red}{2}x+\huge\color{red}{6}=0 } \]see the a b c ? plug them into the quadratic formula.

OpenStudy (anonymous):

\[-1 \pm \sqrt{-1 + 4*2*6} / 2*2\]

OpenStudy (anonymous):

Like that?

OpenStudy (solomonzelman):

Not exactly....

OpenStudy (anonymous):

Then how would I do it??

OpenStudy (solomonzelman):

Sorry your equation was\[x^2+2x-6=0\] \[\huge\color{red}{ \frac{-2±\sqrt{ 1^2-4 \times 2 \times (-6)} }{2 \times 2} }\]

OpenStudy (solomonzelman):

\[\huge\color{red}{ \frac{-2±\sqrt{49}}{4} }\]

OpenStudy (solomonzelman):

\[\huge\color{red}{ \frac{-2±7}{4} }\]you tell me what the answers are....

OpenStudy (anonymous):

@SolomonZelman those are what I got. Seems odd though.

OpenStudy (solomonzelman):

Well, it's right though....

OpenStudy (anonymous):

Really? Haha alright then. Thanks a bunch!

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