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x in (-oo:+oo)
x*((9-x)/3) = 3 // - 3
x*((9-x)/3)-3 = 0
(x*(9-x))/3-3 = 0
(x*(9-x))/3+(-3*3)/3 = 0
x*(9-x)-3*3 = 0
9*x-x^2-9 = 0
9*x-x^2-9 = 0
9*x-x^2-9 = 0
DELTA = 9^2-(-9*(-1)*4)
DELTA = 45
DELTA > 0
x = (45^(1/2)-9)/(-1*2) or x = (-45^(1/2)-9)/(-1*2)
x = (3*5^(1/2)-9)/(-2) or x = (-3*5^(1/2)-9)/(-2)
(x-((3*5^(1/2)-9)/(-2)))*(x-((-3*5^(1/2)-9)/(-2))) = 0
((x-((3*5^(1/2)-9)/(-2)))*(x-((-3*5^(1/2)-9)/(-2))))/3 = 0
((x-((3*5^(1/2)-9)/(-2)))*(x-((-3*5^(1/2)-9)/(-2))))/3 = 0 // * 3
(x-((3*5^(1/2)-9)/(-2)))*(x-((-3*5^(1/2)-9)/(-2))) = 0
( x-((-3*5^(1/2)-9)/(-2)) )
x-((-3*5^(1/2)-9)/(-2)) = 0 // + (-3*5^(1/2)-9)/(-2)
x = (-3*5^(1/2)-9)/(-2)
( x-((3*5^(1/2)-9)/(-2)) )
x-((3*5^(1/2)-9)/(-2)) = 0 // + (3*5^(1/2)-9)/(-2)
x = (3*5^(1/2)-9)/(-2)
x in { (-3*5^(1/2)-9)/(-2), (3*5^(1/2)-9)/(-2) }
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