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x in (-oo:+oo)
Y = (1/6)*x^2-x-3 // - (1/6)*x^2-x-3
Y-((1/6)*x^2)+x+3 = 0
Y+(-1/6)*x^2+x+3 = 0
Y-1/6*x^2+x+3 = 0
DELTA = 1^2-(-1/6*4*(Y+3))
DELTA = 2/3*(Y+3)+1
2/3*(Y+3)+1 = 0
2/3*(Y+3)+1 = 0
2/3*Y+3 = 0
2/3*Y+3 = 0
2/3*Y+3 = 0 // - 3
2/3*Y = -3 // : 2/3
Y = -3/2/3
Y = -9/2
DELTA = 0 <=> t_1 = -9/2
x = -1/(-1/6*2) i Y = -9/2
x = 3 i Y = -9/2
( x = ((2/3*(Y+3)+1)^(1/2)-1)/(-1/6*2) or x = (-(2/3*(Y+3)+1)^(1/2)-1)/(-1/6*2) ) i Y > -9/2
( x = -3*((2/3*(Y+3)+1)^(1/2)-1) or x = 3*((2/3*(Y+3)+1)^(1/2)+1) ) i Y > -9/2
Y+9/2 > 0
Y+9/2 > 0 // - 9/2
Y > -9/2
x in { 3, -3*((2/3*(Y+3)+1)^(1/2)-1), 3*((2/3*(Y+3)+1)^(1/2)+1) }
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