(14х - 1) ( 2 +х) = (2х-8) (7х+1)
28х + 14х² - 2 - х = 14х² + 2х - 56х - 8
27х + 14х² - 2 = 14х² - 54х - 8
27х +14х² - 14х² + 54х = - 8+2
81х = -6
х= - 6 : 81 = - 6/81
х= - 2/27
проверим:
(14 * (-2/27) - 1 ) ( 2 + (-2/27)) = ( 2 * (-2/27) - 8)( 7 * (-2/27) + 1 )
(- 28/27 - 1) * 1 25/27 = (-4/27 - 8) ( - 14/27 + 1)
-55/27 * 52/27 = -220/27 * 13/27
- 2860/729 = - 2860/729
- 3 673/729 = - 3 673/729