Quadratic Formula:

MEMORIZE THIS FORMULA. You will need it way too often to always look it up.

If ax² + bx + c = 0, then

Notice this can also be written as TWO answers:

= [ -b + (b² – 4ac)^1/2 ] / 2a OR [ -b – (b² – 4ac)^1/2 ] / 2a

So if you have a problem that says something like:

x² + 6x + 3 = 0, solve for x then you can simply use the quadratic equation to find the solution(s):

x = [-6 + (6² – 4*1*3)^1/2 ] / 2*1 OR [-6 – (6² – 4*1*3)^1/2 ] / 2*1

= [-6 + (36 – 12)^1/2 ] / 2 OR [ -6 – (36 12)^1/2 ] / 2

= [-6 + ] / 2 OR [-6 – ] / 2

= [-6 + ] / 2 OR [-6 – ] / 2

= [-6 + ] / 2 OR [-6 – ] / 2

= [-6 + 2*] / 2 OR [-6 – 2*] / 2

= OR

= OR