20 / ( X + 4 ) - 8 = - X
Общий знаменатель ( Х + 4 ) ; Х ≠ - 4
20 - 8 * ( X + 4 ) = - X * ( X + 4 )
20 - 8X - 32 = - X^2 - 4X
- 12 - 8X = - X^2 - 4X
X^2 - 8X + 4X - 12 = 0
X^2 - 4X - 12 = 0
D = 16 + 48 = 64 ; √ D = 8
X1 = ( 4 + 8 ) : 2 = 6
X2 = ( 4 - 8 ) : 2 = - 2
ОТВЕТ 6 и ( - 2 )