SOLUTION: Can I get help with this one too: solve by completing the square 2x^2=2x+15 answer choices: a. 1 +or- square root 29 ----------- --------- 2 b. 1 +or- sq

Algebra ->  Square-cubic-other-roots -> SOLUTION: Can I get help with this one too: solve by completing the square 2x^2=2x+15 answer choices: a. 1 +or- square root 29 ----------- --------- 2 b. 1 +or- sq      Log On


   



Question 91725: Can I get help with this one too: solve by completing the square
2x^2=2x+15
answer choices:
a. 1 +or- square root 29
---------------------
2
b. 1 +or- square root 31
---------------------
2
c. 2 +or- square root 22
---------------------
2

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
2x^2=2x+15 ... 2x^2-2x-15=0
completing the square - step-by-step ... for ax^2+bx+c=0
1) by dividing or multiplying, set the coefficient of the squared term equal to one ... x^2+(b/a)x+(c/a)=0
2) by adding or subtracting, set the constant term (c/a) equal to zero ... x^2+(b/a)x=-(c/a)
3) add the square of one half of the x coefficient to both sides ... x^2+(b/a)x+(b/(2a))^2=-(c/a)+(b/(2a))^2
4) take the square root of both sides ... x%2B%28b%2F%282a%29%29=sqrt%28%28b%5E2-4ac%29%2F%284a%5E2%29%29 , realizing the root is positive AND negative

x-(1/2)=sqrt%2831%29%2F2 ... answer (b)