Question 91725
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+(b/(2a))=sqrt((b^2-4ac)/(4a^2))}}} , realizing the root is positive AND negative


x-(1/2)={{{sqrt(31)/2}}} ... answer (b)