Question 93560
<pre><b>
Is the following trinomial a perfect square?
x^2+8x-16 
Thank you

How to test a trinomial to see if it is a perfect square:

1. Find square roots of first and last terms.
2. Multiply them together.
3. Double what you have so far.
4. Do you get the middle term or the middle term with the opposite sign?
   If so the trinomial is a perfect square.

{{{x^2+8x-16}}}

Oh,oh, last term is negative and I can't get the square root of it.
So no, it's not a perfect square.

If it had been {{{x^2+8x+16}}} or {{{x^2-8x+16}}} it would have been,
but if the last sign is negative, it never can be a perfect square.
The last term must be positive.

Edwin</pre>