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D( x )
x = 0
x^2 = 0
x = 0
x = 0
x^2 = 0
x^2 = 0
1*x^2 = 0 // : 1
x^2 = 0
x = 0
x in (-oo:0) U (0:+oo)
4-(1/x)-(9/(x^2)) = 0
4-x^-1-9*x^-2 = 0
t_1 = x^-1
4-9*t_1^2-1*t_1^1 = 0
4-9*t_1^2-t_1 = 0
DELTA = (-1)^2-(-9*4*4)
DELTA = 145
DELTA > 0
t_1 = (145^(1/2)+1)/(-9*2) or t_1 = (1-145^(1/2))/(-9*2)
t_1 = (145^(1/2)+1)/(-18) or t_1 = (1-145^(1/2))/(-18)
t_1 = (145^(1/2)+1)/(-18)
x^-1-((145^(1/2)+1)/(-18)) = 0
1*x^-1 = (145^(1/2)+1)/(-18) // : 1
x^-1 = (145^(1/2)+1)/(-18)
-1 < 0
1/(x^1) = (145^(1/2)+1)/(-18) // * x^1
1 = ((145^(1/2)+1)/(-18))*x^1 // : (145^(1/2)+1)/(-18)
-18*(145^(1/2)+1)^-1 = x^1
x = -18*(145^(1/2)+1)^-1
t_1 = (1-145^(1/2))/(-18)
x^-1-((1-145^(1/2))/(-18)) = 0
1*x^-1 = (1-145^(1/2))/(-18) // : 1
x^-1 = (1-145^(1/2))/(-18)
-1 < 0
1/(x^1) = (1-145^(1/2))/(-18) // * x^1
1 = ((1-145^(1/2))/(-18))*x^1 // : (1-145^(1/2))/(-18)
-18*(1-145^(1/2))^-1 = x^1
x = -18*(1-145^(1/2))^-1
x in { -18*(145^(1/2)+1)^-1, -18*(1-145^(1/2))^-1 }
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