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mix786
Oct 1, 2007, 08:36 AM
Complete the square as an aid in graphing :
y = -x^2 + 8x - 12

Anyone?

galactus
Oct 1, 2007, 01:57 PM
Multiply through by -1 to get rid of the negative in front of the x^2.

Then use the formula:

a(x+\frac{b}{2a})^{2}+c-\frac{b^{2}}{4a}

mix786
Oct 2, 2007, 07:33 AM
shouldn't it be this way:
(x + a)^2 + k

mix786
Oct 2, 2007, 07:39 AM
I think it should be like this:

y = -x^2 + 8x - 12
-y = x^2 - 8x + 12
(x + a)^2 + k
x^2 - 8x place ( ) around it
-y = (x^2 - 8x ) + 12
-y = (x^2 - 8x + 1 ) + 12 - 1
right way?

mix786
Oct 2, 2007, 07:50 AM
-y = (x - 7)^2 + 11

mix786
Oct 2, 2007, 09:05 AM
Hello anyone here to help me out

iamthetman
May 7, 2008, 01:10 PM
y = -x^2 + 8x - 12
-y = x^2 - 8x + 12
-y = (x^2 - 8x +16) + 12 - 16
-y = (x-4)^2 - 4
y = -(x-4)^2 + 4