If you notice that the first term is a perfect square, and the second term is a perfect square, and you have a negative here, we can say that it is "the difference of two squares." What we want to do ...

#45 Square differences Set by Alison Kiddle The number 9 can be written as a difference of two squares as 3 2 – 0 2 = 9 – 0 = 9.