55 - ( 6 - x ) = 15 - ( - 6 )
=> 55 - 6 + x = 15 + 6
=> 49 + x = 21
=> x = 21 - 49
=> x = - 28
Vậy x = - 28
55-(6-x)=15-(-6)
55-(6-x)=21
6-x=55-21=34
x=6-34=-28
55-(6-x)=15-(-6)
55-(6-x)=21
6-x=55-21=34
x=6-34=-28
55-(6-x)=15-(-6)
55-(6-x)=21
6-x=55-21
6-x=34
x=6-34
x=-28
tớ nghĩ là 55-6+x=15+6
49+x=21
x=21-49
x=-28
nhưng tớ chưa chắc đâu
55-(6-x)=15-(-6)
=>55-6+x=21
=>x=21-55+6
=>x=-28