SOLUTION: 2x^2-2x+7=0 I have to solve this by completing the square. I solved it but I'm unsure of my answer, I got x= 1/2 + or - i times radical 13 over 2.

Algebra.Com
Question 171112: 2x^2-2x+7=0
I have to solve this by completing the square. I solved it but I'm unsure of my answer, I got x= 1/2 + or - i times radical 13 over 2.

Found 2 solutions by jim_thompson5910, solver91311:
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
You are correct. There are a number of ways to verify your answer, but you can plug in the answer back into the equation and simplify.
Answer by solver91311(24713)   (Show Source): You can put this solution on YOUR website!
Complete the square on

Step 1, starting from a quadratic in standard form like you have is to put the constant term on the right:



Step 2, if the coefficient on the term is other than 1, divide by that coefficient.



Step 3, divide the resulting coefficient on the term by 2 and square the result



Step 4, add this result to both sides of your equation and collect terms





Step 5, the above result has a perfect square on the left (hence the term "completing the square"), so factor it:



Step 6, take the square root of both sides:

or

Which leads us to a great big oops! because you can't take the square root of a negative number. The solution is to use the imaginary number which is defined as , leaving us with:

or
or
or

Step 7, isolate and simplify in each equation





If you want the exact representation of the roots of the given equation, you are done. If you need a numerical approximation of the imaginary parts of your complex numbers, get out your calculator.

Multiplying to verify that the product is, in fact, , is left as an exercise for the student. Alternatively, you could just trust me.





RELATED QUESTIONS

Problem regarding {{{(2x+1)/(3x-1) > 1}}} I actually know how to solve it. I solved in (answered by Fombitz,MathTherapy)
Can you help me solve this equation 2x^2+8x-7=-2 by completing the square? I got this... (answered by richwmiller,josmiceli,lwsshak3)
Please solve this problem ASAP. I have a test tomorrow and I am doing extra practice to... (answered by jim_thompson5910,josmiceli)
Please solve this problem ASAP. I have a test tomorrow and I am doing extra practice to... (answered by josgarithmetic,Alan3354,rothauserc)
Please help, it says to solve by completing the square. x^2-3x+1=0 What I got for this... (answered by vleith)
Please help. This one I think I have solved it, but I am unsure of what the solution... (answered by stanbon)
I need help with this problem. I have solved it and I got the answer x-5/2 but its not... (answered by user_dude2008)
Please help me solve 9x^2+25y^2-36x+50y-164=0 I know I have to solve by completing the (answered by lwsshak3)
7.) Solve by completing the square. 2x^2+x-6=0 the answer shows -2,3/2 I am not sure (answered by jim_thompson5910)