\(9-\dfrac{y}{18}=\dfrac{1}{3}\)
\(\Leftrightarrow\dfrac{y}{18}=9-\dfrac{1}{3}\)
\(\Leftrightarrow\dfrac{y}{18}=\dfrac{27}{3}-\dfrac{1}{3}\)
\(\Leftrightarrow\dfrac{y}{18}=\dfrac{26}{3}\)
\(\Leftrightarrow3y=18\times26\)
\(\Leftrightarrow3y=468\)
\(\Leftrightarrow y=156\)
:V?
\(\dfrac{9-y}{18}=\dfrac{1}{3}\)
\(\Leftrightarrow9-y=\dfrac{1}{3}\times18\)
\(\Leftrightarrow9-y=6\)
\(\Leftrightarrow y=3\)
Chọn C
:)