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D( x )
x-3 = 0
3*x-9 = 0
x-3 = 0
x-3 = 0
x-3 = 0 // + 3
x = 3
3*x-9 = 0
3*x-9 = 0
3*x-9 = 0 // + 9
3*x = 9 // : 3
x = 9/3
x = 3
x in (-oo:3) U (3:+oo)
x/(3*x-9)-1 = 1/(x-3) // - 1/(x-3)
x/(3*x-9)-(1/(x-3))-1 = 0
x/(3*x-9)-(x-3)^-1-1 = 0
x/(3*x-9)-1/(x-3)-1 = 0
(x*(x-3))/((3*x-9)*(x-3))+(-1*(3*x-9))/((3*x-9)*(x-3))+(-1*(3*x-9)*(x-3))/((3*x-9)*(x-3)) = 0
x*(x-3)-1*(3*x-9)-1*(3*x-9)*(x-3) = 0
x^2-3*x^2-6*x+18*x-27+9 = 0
12*x-2*x^2-18 = 0
12*x-2*x^2-18 = 0
2*(6*x-x^2-9) = 0
6*x-x^2-9 = 0
DELTA = 6^2-(-9*(-1)*4)
DELTA = 0
x = -6/(-1*2)
x = 3 or x = 3
2*(x-3)^2 = 0
(2*(x-3)^2)/((3*x-9)*(x-3)) = 0
(2*(x-3)^2)/((3*x-9)*(x-3)) = 0 // * (3*x-9)*(x-3)
2*(x-3)^2 = 0
x-3 = 0 // + 3
x = 3
x in { 3}
x belongs to the empty set
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