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4x^2-4x-27

 May 26, 2014

Best Answer 

 #2
avatar+118703 
+5

I think this is an odd question.

Usually completing the square is done as a quadratic equation solving technique.  

But if you just want to know what constant needs to be added to make it a perfect square then this is what I'd do.

(it is very similar to what heureka has done)

4x24x27=4(x2x274)=4(x21x+14284)=4(x21x+14284)=4(x21x+14)28=22(x212x+14)28=22(x12)228=(2(x12))228=(2x1)228

So the expression would be a perfect square if 28 were added.

 May 27, 2014
 #1
avatar+26397 
+7

4x24x27=4(x2x)27=4(x2x+(12)2(12)2)27=4((x12)214)27=4(x12)24427=4(x12)2127=4(x12)228

.
 May 26, 2014
 #2
avatar+118703 
+5
Best Answer

I think this is an odd question.

Usually completing the square is done as a quadratic equation solving technique.  

But if you just want to know what constant needs to be added to make it a perfect square then this is what I'd do.

(it is very similar to what heureka has done)

4x24x27=4(x2x274)=4(x21x+14284)=4(x21x+14284)=4(x21x+14)28=22(x212x+14)28=22(x12)228=(2(x12))228=(2x1)228

So the expression would be a perfect square if 28 were added.

Melody May 27, 2014

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