SOLUTION: Solve by completing the square : 3x^2-6x-9=0 please show work thanks.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve by completing the square : 3x^2-6x-9=0 please show work thanks.      Log On


   

Question 869013: Solve by completing the square :
3x^2-6x-9=0
please show work thanks.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
First, the equation can be simplified:
%281%2F3%29%283x%5E2-6x-9%29=%281%2F3%29%2A0
x%5E2-2x-3=0

Then, the term to use for Completing the Square is %28-2%2F2%29%5E2=1.

x%5E2-2x%2B1-1-3=0
%28x%5E2-2x%2B1%29-1-3=0
%28x-1%29%5E2-4=0
You can finish this for x.

Study this: Completing the Square to Solve General Quadratic Equation