\(\left[7\times13+8\times13\right]:\left[9\frac{2}{3}-y\right]=39\)
\(\left[\left(7+8\right)\times13\right]:\left[\frac{29}{3}-y\right]=39\)
\(\left[15\times13\right]:\left[\frac{29}{3}-y\right]=39\)
\(195:\left[\frac{29}{3}-y\right]=39\)
\(\frac{29}{3}-y=195:30\)
\(\frac{29}{3}-y=\frac{13}{2}\)
\(y=\frac{29}{3}-\frac{13}{2}\)
\(y=\frac{19}{6}\)
Học tốt #
[ 7 x 13 + 8 x 13 ] : [ \(9\frac{2}{3}\) - y ] = 39
[ 13 x ( 7 + 8 )] : [ \(9\frac{2}{3}\)- y ] = 39
[ 13 x 15 ] : [\(9\frac{2}{3}\) - y ] = 39
195 : [\(\frac{29}{3}\) - y ] = 39
[ \(\frac{29}{3}\) - y ] = 195 : 39 (*1 )
[\(\frac{29}{3}-y\)] = 5
y = \(\frac{29}{3}-5\)
y = \(\frac{14}{3}\)
\(\left(7.13+8.13\right)\div\left(9\frac{2}{3}-y\right)=39\)
\(\Rightarrow\left(91+104\right)\div\left(\frac{29}{3}-y\right)=39\)
\(\Rightarrow195\div\left(\frac{29}{3}-y\right)=39\)
\(\Rightarrow\frac{29}{3}-y=195\div39\)
\(\Rightarrow\frac{29}{3}-y=5\)
\(\Rightarrow y=\frac{29}{3}-5\)
\(\Rightarrow y=\frac{14}{3}\)
Vậy \(y=\frac{14}{3}\)