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Solve the quadratic equation by completing the square.
x^212x+7=0
 5 months ago
 5 months ago
Solve the quadratic equation by completing the square. x^212x+7=0
 5 months ago
 5 months ago

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SolomonZelmanBest ResponseYou've already chosen the best response.1
add 29 to both sides.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
can you add 29 to both sides?
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Both. \[x^212+7+29=0+29\]
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
To make the left side into perfect square because you have to have (6) (6) which equals 36.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
x^2  12x + 7 = 0 x^2  12x = 7 x^2  12x + (12/2)^2 = (12/2)^2  7 x^2  12x + 36 = 36  7 (x  6)^2 = 29 Take square root of both sides to finish solving for x
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
Oh. Okay. I still don't quite get it, but lets move on. What shall I do next? :D
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
Uhh... which one is right?
 5 months ago

gorvBest ResponseYou've already chosen the best response.1
x^22*x*6+7=0 x^22*x*6+3636+7=0 (x^22*x*6+36)29=0 (x6)^229=0 (x6)^2=29 x6=29^1/2 x=(29)^1/2+6
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
Are all of these right, just in different ways?
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
You add 36 to both sides, not 29
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
@Hero, no you add 29, because that makes the left side into perfect square. @Emily778, I know what you are confused about, lets learn how to complete the square.
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
I'll just do this x^2  12x + 7 = 0 x^2  12x = 7 x^2  12x + (12/2)^2 = (12/2)^2  7 x^2  12x + 36 = 36  7 (x  6)^2 = 29
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
@SolomanZelman, if that's true, then explain how I got my result
 5 months ago

gorvBest ResponseYou've already chosen the best response.1
actually in (a+b)^2=a^2+b^2+2ab here 2ab is 12x=2*x*6 so u need to make b^2 that is 36
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
I know exactly how the process works and what to add to both sides.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
@Emily778, do you get how I came up with 29? lets do a different example. GUYS PLEASE, LETS TEACH HER, NOT DO HER WORK> She needs to understand.
 5 months ago

gorvBest ResponseYou've already chosen the best response.1
@hero if u will add 29 both side than on x^212x+7+29=29 x^212x+36=29
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
She'll only understand if those teaching know what they are talking about
 5 months ago

gorvBest ResponseYou've already chosen the best response.1
@hero plzz plzzzz plzzzz for god sake use little of ur mind
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
@Emily778, do you get how I came up with 29? Do you want to learn how to complete the square?
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
I think @Emily778 already has it figured out lol
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
MODERATOR, please don't ruin the thread, and confuse teh asker, lets teach her!
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
@Hero What do I do after this? Or is it already done? x^2  12x + 7 = 0 x^2  12x = 7 x^2  12x + (12/2)^2 = (12/2)^2  7 x^2  12x + 36 = 36  7 (x  6)^2 = 29
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Sorry If I was offensive, @Hero .
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Finish solving for x @Emily778
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Take the square root of both sides
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
Can you show me how? I am so confused:(
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
@Emily778 PLEASE read this CAREFULLY. Do you know how to come up with the number that you have to add to both sides to ake the left side into a perfect square?
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
to make the left side...typo
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Emily, do you get it conceptually?
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Add 6 to both sides to finish solving for x
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
so, like this @Hero (x6)^2+6=29+6?
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
@Emily778, please observe what I did above first
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
I think you missed that last bit I posted in a drawing
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
oh, you have to square root first?
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Yes you can't do anything until you take the square root of both sides.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
@SolomonZelman, I assure you that we're supposed to add 36 to both sides. I wouldn't tell you anything wrong here.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
If you don't believe me, I have ways of convincing you.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
For one, I know you would never argue with WolframAlpha.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Hero, how does 36 make the left side into a perfect square, it is \[x^2+12x+7=0\]
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Hang on, @SolomonZelman, WolframAlpha is undefeated.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
I meant\[x^212x+7=0\]
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
okay, so it's actually x6+6=+=sqrt29=6?
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Well yes it is then.
 5 months ago

nincompoopBest ResponseYou've already chosen the best response.1
omg don't argue with @Hero
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
@Hero, I am sorry to say this, but you have to rvw over some staff.
 5 months ago

nincompoopBest ResponseYou've already chosen the best response.1
he is correct and I am telling you it
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
@hero okay, so it's actually x6+6=+=sqrt29=6?
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Do you guys know how to complete the square, you don't need any online calculator for this. Idk how to even tell you this. you help with hard staff that I have no clue about, and make a simple error, in completing a square.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Don't tell me 1+1=4
 5 months ago

nincompoopBest ResponseYou've already chosen the best response.1
I know I do not need a calculator and I know he is correct
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Notice that wolframalpha says to add 36 to both sides.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
In this here link: http://tr.im/4klyc
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
maybe you put in 7, instead of +7.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
OK, when you subtract 7, but you can just add 29, without subtracting 7.
 5 months ago

Emily778Best ResponseYou've already chosen the best response.1
Thankyou! Is that it @Hero
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
There's only one correct way to do it @SolomonZelman. Wolframalpha shows the steps. Go review them.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
@Emily778, I think you have it but review your symbology for mistakes and check the link on WolframAlpha
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
@Hero it wastes a step on subtracting 7 from both sides, you still get the same thing, \[x^212+36=29\] Do you see my point?
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Do you guys just argue, or actually READ MY REPLIES?
 5 months ago

nincompoopBest ResponseYou've already chosen the best response.1
solomon, study more before you question
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
@nincompoop, you obviously didn't understand what i said.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Do you understand what I said, I don't need to study, I am fine.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
@SolomonZelman, there's a difference between wasting steps and skipping steps.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Skipping steps leads to confusion
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
I am not saying the Wolframalpha is wrong, it just has a different way of showing... Yes, my bad, perhaps I skipped it, not wasted.... My teacher told me that both ways are valid, and to me that makes perfect sense. And YES, instead of arguing lets continue studying.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
I still think though, that emily didn't get it conceptually.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
That was quite offensive.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Yes, but some things can be figured out through selfstudy, observation and understanding. One thing is for sure. She surely won't get it if she is fed incorrect info.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
True, and I was trying to ask emily if she figured out the first step(s) in completing the square.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Yes, me too, that's why I kept on asking that.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
By the way @SolomonZelman, I'm fully aware of your method of doing it. But I abandoned it after I realized that steps were being skipped. It is wrong for teachers to teach it that way.
 5 months ago

nincompoopBest ResponseYou've already chosen the best response.1
couldn't agree more
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Well, not that they taught me that, but didn't get any points off.
 5 months ago

nincompoopBest ResponseYou've already chosen the best response.1
it's cool can't teach someone about skipping when that person barely knows anything to begin with
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
I don't really see the difference between subtracting seven at first or not. To me it makes perfect sense to do my way.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
I see your point though....
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
And she still hasn't figure it out conceptually, just got the answer and left.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
@nincompoop, actually in biology that could be true, like when parents (or future parents) combine or whatever the word for that is... LIKE twins.
 5 months ago

nincompoopBest ResponseYou've already chosen the best response.1
it's called precision
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
\(\huge {\color{green} {Yup,} }\) forgot the name for this, I learned that last year.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
\(\huge {\color{green} {H} }\)\(\huge {\color{blue} {a} }\)\(\huge {\color{red} {v} }\)\(\huge {\color{orange} {e} }\) \(\huge {\color{purple} {a} }\) \(\huge {\color{lightblue} {n} }\)\(\huge {\color{grey} {i} }\)\(\huge {\color{brown} {g} }\)\(\huge {\color{lightgreen} {h} }\)\(\huge {\color{yellow }{t} }\)\(\huge {\color{darkgreen } {!} }\)
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
The difference between the methods is, one is systematic, and the other is not. The nonsystematic method is an approach that some would refer to as improper methodology.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
\[\(\huge {\color{green} {B^{Y^{E ^{!}}}} }\)\]
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Didn't delete the parenthesis....
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
The method I use can be generalized to this: You begin with x^2 + bx  c = 0 add c to both sides: x^2 + bx = c Then add (b/2)^2 to both sides: x^2 + bx + (b/2)^2 = (b/2)^2 + c
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
This is a systematic approach and you end up with (x + b/2)^2 = b^2/4 + c
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
Well, then improper methodology just shows that the person who did the steps is SMART.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Now let's see @SolomonZelman explain his method in a systematic, generalized manner.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
I would just use an example similar to the one we solved just now.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Examples are not generalized. And they don't show the systematic methodology.
 5 months ago

HeroBest ResponseYou've already chosen the best response.1
Systematic methods have a better chance of being understood than nonsystematic methods.
 5 months ago

SolomonZelmanBest ResponseYou've already chosen the best response.1
OK, I already said that I agree that to start teaching, systematic.... but not using it still shows that the solver is smarter.
 5 months ago
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