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D( a )
a-4 = 0
4-a = 0
a-4 = 0
a-4 = 0
a-4 = 0 // + 4
a = 4
4-a = 0
4-a = 0
4-a = 0 // - 4
-a = -4 // * -1
a = 4
a in (-oo:4) U (4:+oo)
(a^2)/(a-4)+(2*a+8)/(4-a) = 0
(a^2*(4-a))/((a-4)*(4-a))+((2*a+8)*(a-4))/((a-4)*(4-a)) = 0
a^2*(4-a)+(2*a+8)*(a-4) = 0
6*a^2-a^3-32 = 0
6*a^2-a^3-32 = 0
6*a^2-a^3-32 = 0
{ 1, -1, 2, -2, 4, -4, 8, -8, 16, -16, 32, -32 }
1
a = 1
6*a^2-a^3-32 = -27
1
-1
a = -1
6*a^2-a^3-32 = -25
-1
2
a = 2
6*a^2-a^3-32 = -16
2
-2
a = -2
6*a^2-a^3-32 = 0
-2
a+2
8*a-a^2-16
6*a^2-a^3-32
a+2
a^3+2*a^2
8*a^2-32
-8*a^2-16*a
-16*a-32
16*a+32
0
8*a-a^2-16 = 0
DELTA = 8^2-(-16*(-1)*4)
DELTA = 0
a = -8/(-1*2)
a = 4 or a = 4
a in { 4, 4, -2}
(a-4)^2*(a+2) = 0
((a-4)^2*(a+2))/((a-4)*(4-a)) = 0
((a-4)^2*(a+2))/((a-4)*(4-a)) = 0 // * (a-4)*(4-a)
(a-4)^2*(a+2) = 0
( a+2 )
a+2 = 0 // - 2
a = -2
( a-4 )
a-4 = 0 // + 4
a = 4
a in { 4}
a = -2
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