How do you solve 9x^2+12x+4=0 using the quadratic formula?

1 Answer
Nghi N.
Mar 30, 2016

x = (-2/3)(1 +- sqrt2)

Explanation:

Use the improved quadratic formula:
D = d^2 = b^2 - 4ac = 144 + 144 = 288 --> d = +-sqrt(144*2) =
= +- 12sqrt2
There are 2 real roots:
x = -b/(2a) +- d/(2a) = -12/18 +- 12sqrt2/18 =
- 2/3 +- (2/3)sqrt2 = (-2/3)(1 +- sqrt2)

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