SOLUTION: Solve the equation by completing the square. 2x^2-x-2=0 What I've tried 2x^2-x-(1/2)^2=2-(1/2)^2 (2x-(1/2))^2=(9/4) 2x-(1/2)=+/-(3/2) 2x=2 or -1 X=1 or -(1/2) Please

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve the equation by completing the square. 2x^2-x-2=0 What I've tried 2x^2-x-(1/2)^2=2-(1/2)^2 (2x-(1/2))^2=(9/4) 2x-(1/2)=+/-(3/2) 2x=2 or -1 X=1 or -(1/2) Please      Log On


   

Question 606965: Solve the equation by completing the square.
2x^2-x-2=0
What I've tried
2x^2-x-(1/2)^2=2-(1/2)^2
(2x-(1/2))^2=(9/4)
2x-(1/2)=+/-(3/2)
2x=2 or -1
X=1 or -(1/2)
Please show all steps.
Found 2 solutions by Alan3354, mananth:
Answer by Alan3354(69443) About Me  (Show Source):
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
2x%5E2-x-2=0
2x%5E2-x=2

/2
x%5E2-%281%2F2%29x=1
Third term = (1/2* coefficient of middle term)^2
(1/2 * -1/2)^2=1/16
x%5E2-%281%2F2%29x%2B%281%2F16%29=1%2B%281%2F16%29
%28x-%281%2F4%29%29%5E2=17%2F16
take the square root
x-(1/4) = +/-sqrt(17/16)
x= (1/4) +/-sqrt(17)/4)
x= 1.28 OR -0.78