How would I solve this equation using factoring? x^2 - 9 = 0?

Question

How would I solve this equation using factoring? and how would I show my steps?

x^2 - 9 = 0

Thank you!

Answer 1

X^2 - 9 =0

(X-3)(X+3)=0

X= 3 and X= -3

This is the answer if you want more info just read the rest.

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Now how did I get the 3 and -3?

Well, you have X^2 which means you have two X's that need to be used

So, ( X   ) ( X   )

Then, you have to find the numbers that would make the equation equal 0. For 9 there are two possibilities either 9 x 1= 9 or 3 x 3 = 9

I chose 3 because when you foil it out it makes the equation true.

So, ( X  3) (X  3)

how did i know that it is (positive) 3 and (negative) -3 and not just positive 3 and positive 3?

Because if you multiply 3 x 3= 9 but 3 x -3= -9 and you have a - (negative) in your original equation.

So, ( X + 3) (X - 3)

*You can check by FOIL = First Outer Inner Last*

F = X x X = X^2

O =-3 x X = -3X

I = 3 x X = 3X

L = -3 x 3 = -9

SO   X^2 +3X -3X -9 = 0

3X-3X cancels out

X^2 - 9 = 0

Answer 2

Answer=(X+3)(X-3)

If you check your work by FOILing it, then the teacher should be okay with it.  

Answer 3

google it u muppit or ask the question in yahoo answers!!! nerd!

Answer 4

I am assuming that is x squared - 9 =0

first you x2-9+9=0+9

x2=9

3squared =9

if that's not it, please feel free to contact me