SOLUTION: Hello I am trying to figure out how to solve quadratic equations. I have X2-8x-9=0

Question 538112: Hello
I am trying to figure out how to solve quadratic equations. I have X2-8x-9=0
Found 2 solutions by jim_thompson5910, oberobic:
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
Start with the given equation.

Notice that the quadratic is in the form of where , , and

Let's use the quadratic formula to solve for "x":

Start with the quadratic formula

Plug in , , and

Negate to get .

Square to get .

Multiply to get

Rewrite as

Add to to get

Multiply and to get .

Take the square root of to get .

or Break up the expression.

or Combine like terms.

or Simplify.

So the solutions are or

If you need more help, email me at jim_thompson5910@hotmail.com

Also, please consider visiting my website: http://www.freewebs.com/jimthompson5910/home.html and making a donation. Thank you

Jim

Answer by oberobic(2304) (Show Source): You can put this solution on YOUR website!
x^2 -8x -9 = 0
.
So, to factor it you need to find two powers of 9 that have a difference of 1.
-8 = -9+1
.
(x-9)(x+1) = x^2 -8x -9
.
That means x = 9 or -1.
.

.
Done.
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