(x-1 2/5): 10+7 5/12=9 решительно уравнение пож. 1 2/5 значит 1 целая два пятых

(x - 1  2/5) : 10 + 7  5/12 = 9 
(x - 1  2/5) : 10 = 9  -7  5/12
(x - 1  2/5) : 10 = 8  12/12 - 7 5/12
(x - 1  2/5) : 10 = 1  7/12
x - 1   2/5 = 1  7/12 * 10
x - 1  2/5 = 19/12 * 10
x - 1  2/5 = 19/6  * 5
x - 1  2/5 = 95/6
x = 95/6 + 1  2/5
x = 475/30 + 42/30
x = 517/30
x = 17   7/30 

[ Х - 1 ( 2/5 ) ] : 10 + 7 ( 5/12 ) = 9 ; [ Х - 1 ( 2/5 ) ] : 10 = 9 - 7 ( 5/12 ) ; [ Х - 1 ( 2/5 ) ] : 10 = 1 ( 7/12 ) ; Х - 1 ( 2/5 ) = ( 19/12 ) * 10 ; Х - 1 ( 2/5 ) = 190/12 ; Х = 190/12 + 1 ( 2/5 ) ; Х = ( 190/12 ) + ( 7/5 ) ; Х = ( 950/60 ) + ( 84/60 ) ; Х = 1034/60 ; Х = 17 ( 14/60 ) ; Х = 17 ( 7/30 )