Question 48501
<pre><font size = 5><b>IS the following binomial a difference of squares?

9a² - 8b²

No because 8 is not a perfect square.

Edwin
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PS:
Note that if the 8 had been, say a 4, and it had been

9a² - 4b²

instead, then it could have been written as

(3a)² - (2b)²

and then it would have been a difference of squares.

But with the 8 it is not.</pre>