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# Completing the square - GCSE Maths (MathsWatch) watch

1. Currently on MathsWatch doing some completing the square questions and it is asking me to explain how I know x^2 - 6x + 12 is always positive.

I've got absolutely no clue on how to answer this, and if you've used MathsWatch before you'll know how difficult it is to actually get marked right when doing explanation questions.

Any help will be appreciated!

Question attached as an image.
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3. anything squared is always positive or equal to zero, and if you add 3 to it it must be above zero, so positive.
4. (Original post by Angel_Chen)
anything squared is always positive or equal to zero, and if you add 3 to it it must be above zero, so positive.
Thank you!! Makes sense and gave me the marks
5. (Original post by Milli22)
Thank you!! Makes sense and gave me the marks
Np
6. I would explain using the minimum. we that completing the square for f (x) directly shows us the maximum or minimum value of f (x) and the value of x for which this minimum occurs. for our graphs we already know that we have a minimum point since a>0 and from completing the square we know the minimum point of f (x) is 3 hence all other values of f (x) will be 3 or greater than 3 which makes all values positive. so I would write "the minimum value of 3 so f (x) cannot go below 3 hence all values are positive"
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