Completing the square

leahhyson

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Feb 8, 2010
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So I have to make (x+4)^2 into a trinomial by completing the square... I learned this before but I don't remember how. I googled it but nothing that came up helped. Can anyone refresh my memory? I remember i have to divide something in half and something else... I don't know. :p Help me please and thank you! :)
 
leahhyson said:
So I have to make (x+4)^2 into a trinomial by completing the square... I learned this before but I don't remember how. I googled it but nothing that came up helped. Can anyone refresh my memory? I remember i have to divide something in half and something else... I don't know. :p Help me please and thank you! :)

The "normal" method for turning (x + 4)[sup:3vwsrm6m]2[/sup:3vwsrm6m] into a trinomial is to do the indicated multiplication. Remember that squaring a number or an expression means to multiply that number or expression times itself.

So, (x + 4)[sup:3vwsrm6m]2[/sup:3vwsrm6m] means (x + 4)*(x + 4).

To perform this multiplication, multiply each term in the first set of parentheses by each term in the second set of parentheses:

x*x + x*4 + 4*x + 4*4
x[sup:3vwsrm6m]2[/sup:3vwsrm6m] + 4x + 4x + 16

Now, combine like terms:

x[sup:3vwsrm6m]2[/sup:3vwsrm6m] + 8x + 16

There's the trinomial which is equivalent to (x + 4)[sup:3vwsrm6m]2[/sup:3vwsrm6m]
 
I have to make (x+4)^2 into a trinomial by completing the square

You cannot make (x+4)^2 into a trinomial by "completing the square," you can make it into a trinomial simply by "expanding" it:

(x+4)^2 = (x+4)(x+4) = ?

Completing the square is a different procedure.
 
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