<Dd> x 0 = − b ± b 2 − 4 a c 2 a (\ displaystyle x_ (0) = (\ frac (- b \ pm (\ sqrt (b ^ (2) - 4ac))) (2a))) </Dd> <P> This gives the quadratic formula . This way one avoids the technique of completing the square and much more complicated math is not needed . Note this solution is very similar to solving deriving the formula by substitution . </P> <P> Consider the equation </P> <Dl> <Dd> a z 2 + b z + c = 0 (\ displaystyle az ^ (2) + bz + c = 0) </Dd> </Dl>

What is the formula of x + a x + b