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D( x )
x/(9*x^2-1) = 0
9*x^2-1 = 0
4*(3*x+1) = 0
x/(9*x^2-1) = 0
x/(9*x^2-1) = 0
x = 0
9*x^2-1 = 0
9*x^2-1 = 0
9*x^2 = 1 // : 9
x^2 = 1/9
x^2 = 1/9 // ^ 1/2
abs(x) = 1/3
x = 1/3 or x = -1/3
4*(3*x+1) = 0
4*(3*x+1) = 0
3*x+1 = 0 // - 1
3*x = -1 // : 3
x = -1/3
x in (-oo:-1/3) U (-1/3:0) U (0:1/3) U (1/3:+oo)
((2/3)*x-(5/(4*(3*x+1)))-1)/(x/(9*x^2-1)) = 0
((-5/4)*(3*x+1)^-1+(2/3)*x-1)/(x/(9*x^2-1)) = 0
((9*x^2-1)*((2*x)/3-5/4/(3*x+1)-1))/x = 0
(2*x)/3-5/4/(3*x+1)-1 = 0
(-5/4*3)/(3*(3*x+1))+(2*x*(3*x+1))/(3*(3*x+1))+(-1*3*(3*x+1))/(3*(3*x+1)) = 0
2*x*(3*x+1)-1*3*(3*x+1)-5/4*3 = 0
6*x^2+2*x-9*x-15/4-3 = 0
6*x^2-7*x-27/4 = 0
6*x^2-7*x-27/4 = 0
6*x^2-7*x-27/4 = 0
DELTA = (-7)^2-(-27/4*4*6)
DELTA = 211
DELTA > 0
x = (211^(1/2)+7)/(2*6) or x = (7-211^(1/2))/(2*6)
x = (211^(1/2)+7)/12 or x = (7-211^(1/2))/12
(x-((7-211^(1/2))/12))*(x-((211^(1/2)+7)/12)) = 0
((x-((7-211^(1/2))/12))*(x-((211^(1/2)+7)/12)))/(3*(3*x+1)) = 0
((x-((7-211^(1/2))/12))*(x-((211^(1/2)+7)/12)))/(3*(3*x+1)) = 0 // * 3*(3*x+1)
(x-((7-211^(1/2))/12))*(x-((211^(1/2)+7)/12)) = 0
((9*x^2-1)*(x-((7-211^(1/2))/12))*(x-((211^(1/2)+7)/12)))/x = 0
( 9*x^2-1 )
9*x^2 = 1 // : 9
x^2 = 1/9
x^2 = 1/9 // ^ 1/2
abs(x) = 1/3
x = 1/3 or x = -1/3
( x-((211^(1/2)+7)/12) )
x-((211^(1/2)+7)/12) = 0 // + (211^(1/2)+7)/12
x = (211^(1/2)+7)/12
( x-((7-211^(1/2))/12) )
x-((7-211^(1/2))/12) = 0 // + (7-211^(1/2))/12
x = (7-211^(1/2))/12
x in { 1/3}
x in { -1/3}
x in { (211^(1/2)+7)/12, (7-211^(1/2))/12 }
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