508 + (x + 120) = 777
x + 120 = 777 - 508
x + 120 = 209
x = 209 - 120
x = 89
508 + (x + 120) = 777
x + 120 = 777 - 508
x + 120 = 209
x = 209 - 120
x = 89
\(508+\left(x+120\right)=717\)
\(\Rightarrow x+120=717-508\)
\(\Rightarrow x+120=209\)
\(\Rightarrow x=209-120\)
\(\Rightarrow x=89\)
tíc mình nha
508+(x+120)=717
=>(x+120)=717-508
=>(x+120)=209
=>x=209-120
=>x=89