231 - ( x - 6 ) = 1339 : 13
231 - x + 6 = 103
231 - x = 103 - 6
231 - x = 97
x = 231 - 97
x = 134
231-(x-6)=1339:13
=>231-(x-6)=103
=>x-6=231-103
=>x-6=128
=>x=128+6
=>x=134
Hk tốt !
\(231-\left(x-6\right)=1339\div9\)
\(\Leftrightarrow231-x+6=103\)
\(\Leftrightarrow237-x=103\)
\(\Leftrightarrow-x=103-237\)
\(-x=-134\)
\(\Leftrightarrow x=134\)
_Minh ngụy_
231 - ( x - 6 ) = 1339 : 13
231 - ( x - 6 ) = 103
x - 6 = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
Vậy x = 134
