for what real numbers is x is x^2-6x+9 negative?
A. -3
\[x^2-6x+9=\left( x-3 \right)^2 \ge 0\]
@surjithayer how does it go to (x-3)^2> 0
\[x^2-2*x*3+3^2=\left( x-3 \right)^2\] square of a real number is always positive.
\[\left( a-b \right)^2=a^2-2ab+b^2\]
is b?
B
B is not correct. And, a reason for that choice should be given.
what do you mean by that @Directrix
Two Things: The answer to this question is not B. OpenStudy values the Learning process - not the ‘Give you an answer’ process Don’t post only answers - guide the asker to a solution. http://openstudy.com/code-of-conduct
First Factor it to:\[(x-3)(x-3)\] then from here we can analyze the signs of the parts: |dw:1445649286789:dw|
Now guess what happens when we multiply those one either side of 3
those one either side of 3. Take a point, and multiply the signs on either side and see what you get!
for what real numbers is x is x^2-6x+9 **negative**?
so we multiply it by its self?
Name a value of x for which (x - 3) ^2 is negative.
whats a real; number?
Name any number that makes this negative: (x - 3) ^2
Read about real numbers here: http://www.mathsisfun.com/numbers/real-numbers.html
another (x-3)
If you square any real number, the result will never be negative.
true?
Here is the incorrect option B: B. x<-3 or x>3 It says that if I pick any number greater than 3, then (x - 3) ^2 will be negative. Let us test that. (x - 3) ^2 x = 4 (4 - 3) ^2 = 1^2 = 1 which is POSITIVE and not negative. Option B is wrong.
If you square a real number you will NEVER get a negative product.
Ok thanks
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