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September 27, 2016
Posted by **dan** on Sunday, April 25, 2010 at 2:58pm.

x^2 - 12x + ---- = (x - -----)^2

- algebra -
**Mike**, Sunday, April 25, 2010 at 3:42pmThe first blank will have a 36 in it. The second blank will have 6 in it.

When you complete the square in this format, take half of the number in front of x, (called coefficient), and square it. So, in your case, the number in front of x is -12. If I take half of it, it is -6. Then, if I square it, the final result is +36. That goes in the first blank completing the trinomial on the left --> x^2 - 12x + 36

Now, the squared binomial on the right will use the half of the coefficient value. Thus, (x-6)^2 is the final answer on the right.

If you want to check your result, take the (x-6)^2 binomial, and rewrite it as a repeated factor: (x-6)(x-6). Perform FOIL, and you should get x^2 - 12x + 36.

WARNING: Completing the Square only works when the coefficient of the x^2 term is ONE!

Hope this helps! - algebra -
**dan**, Sunday, April 25, 2010 at 4:59pmYes you helped me a lot. Thank you for showing me in steps how to solve this question

- algebra 1 -
**nolan**, Sunday, May 23, 2010 at 8:02pmx^2-18x+___=( )^2