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Mathematics 15 Online
OpenStudy (anonymous):

Solve for m

OpenStudy (anonymous):

\[\sqrt{m-7} = n+3 \]

OpenStudy (whpalmer4):

To get rid of the square root, you need to square both sides. Do you know how to do that?

OpenStudy (anonymous):

\[m^2-49 = n^2 + 9 ?\]

OpenStudy (whpalmer4):

mmm....no. \[\sqrt{m-7} = n+3\]Square both sides\[\sqrt{m-7}*\sqrt{m-7} = (n+3)(n+3)\]\[m-7 = n^2 + 3n + 3n + 9\]Can you solve that?

OpenStudy (anonymous):

I think so ... \[m=n^2+6n+2?\]

OpenStudy (whpalmer4):

Close. But not close enough :-) Try again? How did you move the 7?

OpenStudy (anonymous):

ohhhhh haha sorry add POSITIVE 7 hahaha so, 16 at the end?

OpenStudy (whpalmer4):

yes!

OpenStudy (whpalmer4):

So do you understand how I squared both sides?

OpenStudy (anonymous):

hahaha yep :) Thank you :) You are good at explaining the steps and making sure I understand them :) haha

OpenStudy (anonymous):

I was squaring the individuals :3 haha

OpenStudy (whpalmer4):

Excellent, you wouldn't believe how many people don't realize that doesn't work :-)

OpenStudy (anonymous):

hahaha I was one of 'em :) haha thank you so much, again :)

OpenStudy (whpalmer4):

and easy to demonstrate: 5^2 = 5*5 = 25 (2+3) = 5 (2+3)^2 = (2+3)(2+3) = 25 which doesn't equal 4 + 9!

OpenStudy (whpalmer4):

sometimes trying out algebra expressions with actual numbers like that makes it easier to see why it does (or doesn't) work...

OpenStudy (anonymous):

Yeah, I do that sometimes but I never thought to do it with this kind of question :) haha I am so happy I can finally understand this :)

OpenStudy (whpalmer4):

Another happy customer :-)

OpenStudy (whpalmer4):

Got another to do?

OpenStudy (anonymous):

It is sort of like this, we are just learning about radicals in general but it's this one... https://media.glynlyon.com/g_alg01_2013/8/test15.gif

OpenStudy (anonymous):

It's probably really simple but I just don't know where to start... :\

OpenStudy (anonymous):

I mean it looks simple haha

OpenStudy (whpalmer4):

\[\frac{x}{2}+1 = \sqrt{3}\]Is that it?

OpenStudy (anonymous):

yep

OpenStudy (whpalmer4):

Okay, you know how to do this, I'm sure. It's the radical sign that is making you not so sure... What if you had\[\frac{x}{2}+1=3\]Would you know how to solve that for \(x\)?

OpenStudy (anonymous):

subtract one and multiply by 2

OpenStudy (whpalmer4):

Indeed. And that's just what you do here!

OpenStudy (anonymous):

oh, really??

OpenStudy (whpalmer4):

But you can't subtract the 1 from the 3 underneath the square root sign. Here's what happens: \[\frac{x}{2} + 1 = \sqrt{3}\]Subtract 1 from both sides\[\frac{x}{2}+1-1 = \sqrt{3}-1\]\[\frac{x}{2} = \sqrt{3}-1\]Now what do you do next?

OpenStudy (anonymous):

oh!!! is it \[2\sqrt{3}-2\]

OpenStudy (whpalmer4):

It is!

OpenStudy (whpalmer4):

See, I told you you already knew how to do it :-)

OpenStudy (anonymous):

Hahahaha!!!! Yesssss!! lol thank you soooo much!!!

OpenStudy (anonymous):

lol I've had a good bit of problems in this course that we are working on and I finally get it :D haha I get a little "excited" when I learn how to do a new thing haha

OpenStudy (anonymous):

Thank you so much :)

OpenStudy (whpalmer4):

You're welcome! Actually, reactions like that are why I do this :-)

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