How do you solve x^2 + 9x + 9 = 0 using the quadratic formula?

2 Answers
Binayaka C.
Apr 26, 2016

Root1= -1.146 and Root2 = -7.854

Explanation:

This is quadratic equation where a=1 ;b=9; c=9; b^2-4ac > 0 So roots are real. Roots are -b/(2*a) +- sqrt (b^2-4ac)/(2a) :.Root1 =-9/2+sqrt45/2 = -1.146 and Root2=-9/2-sqrt45/2 = -7.854[Ans]

Nghi N.
Apr 26, 2016

(-9 +- 3sqrt5)/2

Explanation:

y = x^2 + 9x + 9 = 0
Use the improved quadratic formula (Socratic Search)
D = d^2 = b^2 - 4ac = 81 - 36 = 45 --> d = +- 3sqrt5
There are 2 real roots:

x = -b/(2a) +- d/(2a) = -9/2 +- 3sqrt5/2 = (-9 +- 3sqrt5)/2

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