25 - (30 + x) = x - (27 - 8)
=> 25 - 30 - x = x - 19
=> -5 - x = x - 19
=> -5 + 19 = x + x
=> 14 = 2x
=> x = 14:2
=> x = 7.
25 - 30 -x=x-27-8
x+x=25-30+27-8
x+x=14
x=14:2
x=7
ta có :
25 - ( 30 + x ) = x - ( 27 - 8 )
25 - 30 - x = x - 27 + 8
x + x = 25 - 30 + 27 - 8
2x = 14
x = 14 : 2
x = 7