2x^2 + x - 2 = 0 (Problem completing the square)

[ryana]

What am I doing wrong when completing the square or solving for x?

Problem:
2x^2 + x - 2 = 0
Devide by the coefficient of x^2:
x^2 + 1/2x - 1 = 0
Move the constant:
x^2 + 1/2x = 1
Complete the square:
(x + 1/4)^2 = 17/16
Solve for x:
x + 1/4 = the root of 17/16
Answer:
x = -1/4 + OR - the root of 17/16


The correct answer should be: x = -1/4 + OR - the root of 17/4
The answer I get is x = -1/4 + OR - the root of 17/16

 

[tkhunny]

\(\displaystyle \sqrt{16}\;=\;4\)

\(\displaystyle \sqrt{\frac{17}{16}}\;=\;\frac{\sqrt{17}}{4}\)

Are you there, yet?

 

[ryana]

Two days of trying to figure out what I was doing wrong and I just never finished!

Thank you for the amazingly fast answer