SOLUTION: solve by completing the square: 2x^2-x-5=0

Question 137172: solve by completing the square: 2x^2-x-5=0
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
2x^2 - x - 5 = 0
:
When you complete the square, you want the coefficient of x^2 to be 1,
divide the equation by 2, to accomplish this
x^2 - x - = 0
:
Add to both sides, leave a place for the value we need to complete the square
x^2 - x + ___ =
:
Find the third term by dividing the coefficient of x by 2 and squaring it:
Here that would be; which is , we now have:
x^2 - x + = + ; we have to add to both sides
x^2 - x + = + ; find a common denominator so we cam add the fractions
x^2 - x + =
We have perfect square which is:
(x - )^2 =
Find the square root of both sides:
x - = +/-
we can extract the sqrt of 4 in the denominator;
x - = +/-
add 1/4 to both sides
x = +/-
or we can write it
x = +/-
Put it all over a denominator of 4
x =
and
x =
Didthishelp?

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