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D( a )
a = 0
a+3 = 0
a = 0
a = 0
a+3 = 0
a+3 = 0
a+3 = 0 // - 3
a = -3
a in (-oo:-3) U (-3:0) U (0:+oo)
5/a-(3/a)+3+4 = (21/(a+3))*(a+4) // - (21/(a+3))*(a+4)
5/a-((21/(a+3))*(a+4))-(3/a)+3+4 = 0
5/a-21*(a+3)^-1*(a+4)-3*a^-1+3+4 = 0
(-21*(a+4))/(a+3)+5/a-3/a+3+4 = 0
(-21*a*(a+4))/(a*(a+3))+(5*(a+3))/(a*(a+3))+(-3*(a+3))/(a*(a+3))+(3*a*(a+3))/(a*(a+3))+(4*a*(a+3))/(a*(a+3)) = 0
5*(a+3)-21*a*(a+4)-3*(a+3)+3*a*(a+3)+4*a*(a+3) = 0
3*a^2-21*a^2+4*a^2-79*a-3*a+9*a+12*a-9+15 = 0
3*a^2-21*a^2+4*a^2-82*a+9*a+12*a+6 = 0
4*a^2-18*a^2-73*a+12*a+6 = 0
6-14*a^2-61*a = 0
6-14*a^2-61*a = 0
6-14*a^2-61*a = 0
DELTA = (-61)^2-(-14*4*6)
DELTA = 4057
DELTA > 0
a = (4057^(1/2)+61)/(-14*2) or a = (61-4057^(1/2))/(-14*2)
a = (4057^(1/2)+61)/(-28) or a = (61-4057^(1/2))/(-28)
(a-((4057^(1/2)+61)/(-28)))*(a-((61-4057^(1/2))/(-28))) = 0
((a-((4057^(1/2)+61)/(-28)))*(a-((61-4057^(1/2))/(-28))))/(a*(a+3)) = 0
((a-((4057^(1/2)+61)/(-28)))*(a-((61-4057^(1/2))/(-28))))/(a*(a+3)) = 0 // * a*(a+3)
(a-((4057^(1/2)+61)/(-28)))*(a-((61-4057^(1/2))/(-28))) = 0
( a-((4057^(1/2)+61)/(-28)) )
a-((4057^(1/2)+61)/(-28)) = 0 // + (4057^(1/2)+61)/(-28)
a = (4057^(1/2)+61)/(-28)
( a-((61-4057^(1/2))/(-28)) )
a-((61-4057^(1/2))/(-28)) = 0 // + (61-4057^(1/2))/(-28)
a = (61-4057^(1/2))/(-28)
a in { (4057^(1/2)+61)/(-28), (61-4057^(1/2))/(-28) }
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