Question 490458
done by completing the square


subtracting c ___ ax^2 + bx = -c


dividing by a ___ x^2 + (b/a)x = -c/a


adding half of the x-term coefficient, squared ___ x^2 + (b/a)x + (b/2a)^2 = (-c/a) + (b/2a)^2


x^2 + (b/a)x + (b/2a)^2 = (-c/a) + [(b^2)/(4a^2)] ___ x^2 + (b/a)x + (b/2a)^2 = [(-4ac)/(4a^2)] + [(b^2)/(4a^2)]


combining terms and taking sqrt ___ x + (b/2a) = ± [sqrt(b^2 - 4ac)] / 2a


subtracting (b/2a) and combining terms ___ x = {-b ± [sqrt(b^2 - 4ac)]} / 2a