How do you factor and find the zeroes for P(x)= x^2 - 9?

1 Answer
Alan P.
Jun 2, 2015

The zeros of a function P(x) are the values of x for which P(x) = 0

By the difference of squares:

color(white)("XXXXX")x^2-9 = (x+3)(x-3)

If P(x) = 0 then

color(white)("XXXXX")(x+3)(x-3)=0

which can only be true if

either

color(white)("XXXXX")x=-3 or x=+3

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