SOLUTION: please i want to know how to derive the quadratic formular

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Question 1107972: please i want to know how to derive the quadratic formular
Found 2 solutions by Fombitz, Boreal:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Complete the square on a general equation,
ax%5E2%2Bbx%2Bc=0
a%28x%5E2%2B%28b%2Fa%29x%29%2Bc=0
a%28x%5E2%2B%28b%2Fa%29x%2B%28b%2F%282a%29%29%5E2%29%2Bc-b%5E2%2F%284a%5E2%29=0
a%28x%2B%28b%2F%282a%29%29%29%5E2=b%5E2%2F4a-c
Can you complete it from there?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
ax^2+bx+c=0
ax^2+bx=-c
x^2+(b/a)x=-c/a, dividing everything by a
complete the square
(x+(b/2a))^2=-(c/a)+b^2/4a^2, adding the (b/2a)^2 to both sides
(x+(b/2a))^2=(-4ac+b^2)/4a^2, putting everything over a common denominator.
x=-(b/2a) +/- sqrt [(b^2-4ac)/4a^2]
x=(-b/2a)+/- sqrt[(b^2-4ac)]/ 2a
x=(1/2a)(-b+/- sqrt (b^2-4ac))