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D( x )
2*x+6 = 0
4*x+8 = 0
2*x+6 = 0
2*x+6 = 0
2*x+6 = 0 // - 6
2*x = -6 // : 2
x = -6/2
x = -3
4*x+8 = 0
4*x+8 = 0
4*x+8 = 0 // - 8
4*x = -8 // : 4
x = -8/4
x = -2
x in (-oo:-3) U (-3:-2) U (-2:+oo)
5/(2*x+6) = 21/(4*x+8) // - 21/(4*x+8)
5/(2*x+6)-(21/(4*x+8)) = 0
5/(2*x+6)-21*(4*x+8)^-1 = 0
5/(2*x+6)-21/(4*x+8) = 0
(5*(4*x+8))/((2*x+6)*(4*x+8))+(-21*(2*x+6))/((2*x+6)*(4*x+8)) = 0
5*(4*x+8)-21*(2*x+6) = 0
-22*x-86 = 0
(-22*x-86)/((2*x+6)*(4*x+8)) = 0
(-22*x-86)/((2*x+6)*(4*x+8)) = 0 // * (2*x+6)*(4*x+8)
-22*x-86 = 0
-22*x-86 = 0 // + 86
-22*x = 86 // : -22
x = 86/(-22)
x = -43/11
x = -43/11
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