mik tính đc 11 bn nha
\(\left[\left(4x+28\right).3+55\right]:5=35\)
\(\Leftrightarrow\left(4x+28\right).3+55=175\)
\(\Leftrightarrow\left(4x+28\right).3=120\)
\(\Leftrightarrow4x+28=40\)
\(\Leftrightarrow4x=12\)
\(\Leftrightarrow x=3\)
#H
\(\left[\left(4x+28\right).3+55\right]:5=35\)
\(\Leftrightarrow\left(4x+28\right).3+55=35.5\)
\(\Leftrightarrow\left(4x+28\right).3+55=175\)
\(\Leftrightarrow\left(4x+28\right).3=175-55\)
\(\Leftrightarrow\left(4x+28\right).3=120\)
\(\Leftrightarrow4x+28=120:3\)
\(\Leftrightarrow4x+28=40\)
\(\Leftrightarrow4x=12\)
\(\Leftrightarrow x=12:4\)
\(\Leftrightarrow x=3\)
Vậy \(x=3\)