( 1 / X - 4 ) - ( 1 / X + 6 ) = 5 / 28
28 * ( X + 6 ) - 28 * ( X - 4 ) = 5 * ( X - 4 ) * ( X + 6 )
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X ≠ 4 ; X ≠ - 6
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28X + 168 - 28X + 112 = 5 * ( X^2 + 6X - 4X - 24 )
280 = 5X^2 + 10X - 120
5X^2 + 10X - 400 = 0
5 * ( X^2 + 2X - 80 ) = 0
D = 4 + 320 = 324 ; √ D = 18
X1 = ( - 2 + 18 ) : 2 = 8
X2 = ( - 2 - 18 ) : 2 = - 10
Ответ 8 и ( - 10 )