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D( a )
a = 0
a-8 = 0
a = 0
a = 0
a-8 = 0
a-8 = 0
a-8 = 0 // + 8
a = 8
a in (-oo:0) U (0:8) U (8:+oo)
1/(a-8)-5 = 4/a-8 // - 4/a-8
1/(a-8)-(4/a)-5+8 = 0
1/(a-8)-4*a^-1-5+8 = 0
1/(a-8)-4/a-5+8 = 0
(1*a)/(a*(a-8))+(-4*(a-8))/(a*(a-8))+(-5*a*(a-8))/(a*(a-8))+(8*a*(a-8))/(a*(a-8)) = 0
8*a*(a-8)-4*(a-8)-5*a*(a-8)+1*a = 0
8*a^2-5*a^2-3*a+40*a-64*a+32 = 0
8*a^2-5*a^2+37*a-64*a+32 = 0
3*a^2-27*a+32 = 0
3*a^2-27*a+32 = 0
3*a^2-27*a+32 = 0
DELTA = (-27)^2-(3*4*32)
DELTA = 345
DELTA > 0
a = (345^(1/2)+27)/(2*3) or a = (27-345^(1/2))/(2*3)
a = (345^(1/2)+27)/6 or a = (27-345^(1/2))/6
(a-((27-345^(1/2))/6))*(a-((345^(1/2)+27)/6)) = 0
((a-((27-345^(1/2))/6))*(a-((345^(1/2)+27)/6)))/(a*(a-8)) = 0
((a-((27-345^(1/2))/6))*(a-((345^(1/2)+27)/6)))/(a*(a-8)) = 0 // * a*(a-8)
(a-((27-345^(1/2))/6))*(a-((345^(1/2)+27)/6)) = 0
( a-((27-345^(1/2))/6) )
a-((27-345^(1/2))/6) = 0 // + (27-345^(1/2))/6
a = (27-345^(1/2))/6
( a-((345^(1/2)+27)/6) )
a-((345^(1/2)+27)/6) = 0 // + (345^(1/2)+27)/6
a = (345^(1/2)+27)/6
a in { (27-345^(1/2))/6, (345^(1/2)+27)/6 }
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