9-25=(7-x)-(25+7)
( 7 - x ) - ( 25 + 7 ) = 9 - 25
( 7 - x ) - 32 = - 16
7 - x = ( - 16 ) + 32
7 - x = 16
x = 7 - 16
x = - 9
Vậy x = - 9
9 - 25 = ( 7 - x ) - ( 25 + 7 )
x = 7 - 25 - 7 - 9 + 25
x = ( 7 - 7 ) + ( 25 - 25 ) -9
x = 0 + 0 - 9
x= - 9
=> x= - 9
Vậy x = - 9