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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/x+(5*x)/x-3+3 = 90/(x^2)-9 // - 90/(x^2)-9
4/x-(90/(x^2))+(5*x)/x-3+3+9 = 0
4/x-90*x^-2+(5*x)/x-3+3+9 = 0
4*x^-1-90*x^-2+14 = 0
t_1 = x^-1
4*t_1^1-90*t_1^2+14 = 0
4*t_1-90*t_1^2+14 = 0
DELTA = 4^2-(-90*4*14)
DELTA = 5056
DELTA > 0
t_1 = (5056^(1/2)-4)/(-90*2) or t_1 = (-5056^(1/2)-4)/(-90*2)
t_1 = (8*79^(1/2)-4)/(-180) or t_1 = (-8*79^(1/2)-4)/(-180)
t_1 = (8*79^(1/2)-4)/(-180)
x^-1-((8*79^(1/2)-4)/(-180)) = 0
1*x^-1 = (8*79^(1/2)-4)/(-180) // : 1
x^-1 = (8*79^(1/2)-4)/(-180)
-1 < 0
1/(x^1) = (8*79^(1/2)-4)/(-180) // * x^1
1 = ((8*79^(1/2)-4)/(-180))*x^1 // : (8*79^(1/2)-4)/(-180)
-180*(8*79^(1/2)-4)^-1 = x^1
x = -180*(8*79^(1/2)-4)^-1
t_1 = (-8*79^(1/2)-4)/(-180)
x^-1-((-8*79^(1/2)-4)/(-180)) = 0
1*x^-1 = (-8*79^(1/2)-4)/(-180) // : 1
x^-1 = (-8*79^(1/2)-4)/(-180)
-1 < 0
1/(x^1) = (-8*79^(1/2)-4)/(-180) // * x^1
1 = ((-8*79^(1/2)-4)/(-180))*x^1 // : (-8*79^(1/2)-4)/(-180)
-180*(-8*79^(1/2)-4)^-1 = x^1
x = -180*(-8*79^(1/2)-4)^-1
x in { -180*(8*79^(1/2)-4)^-1, -180*(-8*79^(1/2)-4)^-1 }
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