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D( x )
12*x^3 = 0
12*x^3 = 0
12*x^3 = 0
12*x^3 = 0 // : 12
x^3 = 0
x = 0
x in (-oo:0) U (0:+oo)
(36*x^2-(12*x)-18)/(12*x^3) = 0
(36*x^2-12*x-18)/(12*x^3) = 0
36*x^2-12*x-18 = 0
6*(6*x^2-2*x-3) = 0
6*x^2-2*x-3 = 0
DELTA = (-2)^2-(-3*4*6)
DELTA = 76
DELTA > 0
x = (76^(1/2)+2)/(2*6) or x = (2-76^(1/2))/(2*6)
x = (2*19^(1/2)+2)/12 or x = (2-2*19^(1/2))/12
6*(x-((2-2*19^(1/2))/12))*(x-((2*19^(1/2)+2)/12)) = 0
(6*(x-((2-2*19^(1/2))/12))*(x-((2*19^(1/2)+2)/12)))/(12*x^3) = 0
( x-((2*19^(1/2)+2)/12) )
x-((2*19^(1/2)+2)/12) = 0 // + (2*19^(1/2)+2)/12
x = (2*19^(1/2)+2)/12
( x-((2-2*19^(1/2))/12) )
x-((2-2*19^(1/2))/12) = 0 // + (2-2*19^(1/2))/12
x = (2-2*19^(1/2))/12
x in { (2*19^(1/2)+2)/12, (2-2*19^(1/2))/12 }
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