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D( c )
c = 0
c = 0
c = 0
c in (-oo:0) U (0:+oo)
18/c < 9 // - 9
18/c-9 < 0
18*c^-1 < 9
18*c^-1 < 9 // : 18
c^-1 < 9/18
c^-1 < 1/2
1/(c^1) < 1/2
c <> 0
1/(c^1) < 1/2 // * c^2
(c^2)/(c^1) < 1/2*c^2
c^1 < 1/2*c^2
c-1/2*c^2 < 0
c^1*(1-1/2*c) < 0
c < 0
-(abs(c))^1*(1/2*(abs(c))^1+1) < 0 // : -(abs(c))^1
1/2*(abs(c))^1+1 > 0
1/2*(abs(c))^1 > -1 // : 1/2
(abs(c))^1 > -1/1/2
(abs(c))^1 > -2 // ^ 1/1
abs(c) > (-2)^(1/1)
abs(c) > -2
c in (-oo:0)
c < 0
c > 0
c^1*(1-(1/2*c^1)) < 0 // : c^1
1-(1/2*c^1) < 0
1 < 1/2*c^1 // : 1/2
1/1/2 < c^1 // ^ 1/1
(1/1/2)^(1/1) < c
c in (2:+oo)
c > 0
c in (-oo:0) U (2:+oo)
c in (-oo:0) U (2:+oo)
(-oo:0) U (2:+oo)
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