How do you factor x squared minus 1?

Answer 1

x2 -1=(x+1)(x-1)

ans

Answer 2

x2 - 1 = (x + 1)(x - 1)

This comes from a formula that is called "The Difference of Squares."

The formula says that when you are subtracting two square numbers from each other that they can always be factored as such:

a2 - b2 = (a + b)(a - b)

Another example would be to factor x2 - 9.

We could rewrite x2 - 9 as x2 - 32 which when we compare it to the formula above helps us to see that a=x and b=3. This yields the result:

a2 - b2=(a + b)(a - b)

x2 - 32 = (x + 3)(x - 3)

And just for good measure here is another example :)

Factor the following polynomial expression:

x2 - 64

Step 1: Rewrite it as the difference of two squares: x2 - 82

Step 2: Plug in a=x and b=8 into the formula above to get: (x + 4)(x - 4)