check for extraneous solutions.
sqrt x+7-x=1
Please show step by step on how to do this. Thankyou.

- anonymous

check for extraneous solutions.
sqrt x+7-x=1
Please show step by step on how to do this. Thankyou.

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- schrodinger

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- anonymous

Let \(u=\sqrt{x}\), then x = \(u^2\)
Now, the equation becomes
\[u+7-u^2=1\]
Can you do it?

- anonymous

Wat?

- anonymous

@Krazete

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## More answers

- anonymous

I don't get the way you're explaining it to me @RolyPoly

- anonymous

Please make use of parentheses. The way you write problems is sorta confusing.
Is it √(x+7)-x=1 or ...?

- anonymous

I guess. Sorry, it doesn't show parentheses on my math problem.

- anonymous

Is the equation (1)\(\sqrt{ x+7-x} =1\) or (2) \(\sqrt{x}+7-x=1\)?

- anonymous

nvm, i got the answer. Thx

- anonymous

nvm.. I tried wolframalpha. But only get two step by steps each day:(

- anonymous

I'll have to get the answer tomorrow.

- anonymous

It would be better if you know how to solve it, instead of just relying on WolframAlpha.

- anonymous

eh, true. But lets be honest with ourselves, I'm never going to use this advanced of math in the future.

- anonymous

Honestly, I just need credits/passed classes

- anonymous

you can argue all you want, but it's true.

- anonymous

Don't want to argue, just want to help you pass the course and you can learn how to solve it at the same time :)

- anonymous

can you just show me please? I'm 18 lessons behind:(

- nikato

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

- nikato

add x to both sides

- anonymous

It would be a different story if I wasn't that behind

- anonymous

\[\sqrt{x-7-x}=1\]\[\sqrt{x-7}-x=1\]\[\sqrt{x}-7-x=1\]
Which one is your question?

- anonymous

like this @nikato |dw:1388896983931:dw|

- anonymous

the 2nd one @RolyPoly

- nikato

yup

- anonymous

what next?

- nikato

so now u have|dw:1388897108757:dw| now square both sides

- anonymous

i know 9 is the solution

- anonymous

what next?

- nikato

did u square both sides. and simplified it?

- anonymous

how do I simplify it?

- nikato

|dw:1388897450469:dw|does that make sense?

- anonymous

yeah.

- anonymous

what next?

- nikato

subtract x and 7 on both sides so that the equation equal 0

- nikato

|dw:1388897691356:dw|

- anonymous

what next? :D ha

- nikato

|dw:1388897800670:dw| can u factor the right side?

- anonymous

can you show me? eheh

- nikato

|dw:1388898386363:dw|

- anonymous

9?

- anonymous

@nikato

- anonymous

it has to be 9.

- nikato

no, i dont think 9 is a solution. try pluggin it back into the origianl equation. it doesnt work

- nikato

|dw:1388899069611:dw|

- anonymous

then you did it wrong. Ugh. Wolfram said it was 9

- nikato

no, im for sure 9 is not an answer. it doesnt make sense. its one fo those^

- anonymous

@Krazete is he wrong or not?

- anonymous

sorry, nikato. I gotta make sure.

- nikato

yea, its fine. whatever u feel is right

- anonymous

nikato's right.

- anonymous

okayy,, it's just wolfram said the solution was 9. But I guess it's better to have something than nothing at all.

- nikato

maybe u typed in the wrong equation in wolfrma

- anonymous

Look at what Wolfram says under "input." Is it the same as your problem? It might've calculated √x instead of √(x+7). Parentheses are quite important.

- anonymous

nikato, what do I do next? Sorry for doubting you

- nikato

|dw:1388899779946:dw| solve for x. did most of the work. should be easy for u. there are suppose to be 2 answers

- anonymous

one of them is 2.

- nikato

yes. and the other?

- anonymous

o?

- nikato

no, -3. so now u want to find if there is anyextraneous answers

- nikato

plug both back into the equation and see if they make sense|dw:1388900195738:dw|

- anonymous

ugh. How much more is there??

- anonymous

what next?

- nikato

no, this is it. check if both of those equation are true. if they are not, then that "x" is extraneous

- anonymous

it's 1.

- anonymous

thanks. :p

- nikato

WAIT NO. its either 2 or -3. i helped plug in both in for x
the first one is x=2
and the other is x=-3

- anonymous

I did it in my calculator. How'd you get your answer?

- nikato

no, thats not what i meant

- nikato

|dw:1388901004098:dw|

- anonymous

I'm sorry, I still don't get how you got those answers. I got -5 and 1. 1 was correct. -5 was incorrect.

- nikato

yes. so that means -3 is the extraneous answer.
remember how we worked the problem, and got 2 and -3 as the naswer.
however when u plug -3 back into the original equation u get -5 instead of 1. which means the answer doesnt "work" which we call an extraneous answer

- anonymous

so what is the answer???

- nikato

just 2

- nikato

becuz like i said ^ -3 is an extraneous solution

- anonymous

so, I would put "x=2 only"?

- nikato

yup

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