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If we express 3x^2-6x-2 in the form a(x-h)^2+k , then what is a+h+k?

Guest Oct 16, 2018
 #1
avatar+90968 
+2

3x^2  - 6x  - 2        factor out the 3

 

3 (x^2  - 2x  - 2/3)      take 1/2 of 2, square it  = 4...add and subtract it within  the parentheses

 

3(x^2  - 2x + 4  - 2/3  - 4)    factor the first three terms in parentheses ...simplify the rest

 

3 [ (x - 2)^2  -14/3 ]    distribute the 3 across the terms in the brackets

 

3 ( x- 2 )^2  - 14

 

a  = 3     h = 2   and  k = -14

 

And their sum is  -9

 

 

 

cool cool cool

CPhill  Oct 16, 2018
 #3
avatar
+1

Looks like you removed my post Melody, but it's still a load of twaddle.

(Good natured banter, not insulting).

To say that a 1/2 of 2 squared is 4 is just careless, a mistake that any of us could make on a bad day.

Not to pick up the mistake on the next line is even more careless.

Worse though is not checking the result, which for something as simple as this should be routine.

Guest Oct 17, 2018
 #4
avatar+93866 
0

Firstly it was not me who deleted your post although I would have done so if I had seen it first.

 

If I had written this answer I most likely not have checked it.

We make it far too easy for question askers already. I see it as their responsibility to check my answer.

If they copy without understanding then I WANT them to get it wrong!

If they correct it themselves that is good.

If they politely point out the error or ask for guidance because it does not make sense to them that is great. 

That would indicate to me that I am actually teaching them and not just talking to thin air or facilitating mindless cheating.

Melody  Oct 17, 2018
edited by Melody  Oct 17, 2018

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