315+[125-x]=435
125-x=435-315
125-x=120
x=125-120
x=5
\(315+\left(125-x\right)=435\)
\(125-x=435-315\)
\(125-x=120\)
\(x=125-120\)
\(x=5\)
315 + [ 125-x ] = 435
125-x = 435 - 315
125-x = 120
x = 125-120
x = 5
315+(125-x)=435
125-x=435-315
125-x=120
x=125-120
x=5
Vậy x=5