Cách \(1:\)\(\frac{7}{15}x\frac{4}{9}+\frac{4}{9}x\frac{11}{12}\)
\(=\frac{28}{135}+\frac{11}{27}\)
\(=\frac{28}{135}+\frac{11}{27}\)
\(=\frac{28}{135}+\frac{55}{135}\)
\(=\frac{83}{135}\)
Cách \(2:\)\(\frac{7}{15}x\frac{4}{9}+\frac{4}{9}x\frac{11}{12}\)
\(=\frac{4}{9}x\left(\frac{7}{15}+\frac{11}{12}\right)\)
\(=\frac{4}{9}x\left(\frac{84}{180}+\frac{165}{180}\right)\)
\(=\frac{4}{9}x\frac{83}{60}\)
\(=\frac{83}{165}\)
\(\frac{7}{15}x\frac{4}{9}+\frac{4}{9}x\frac{11}{12}\)
C1 = \(\left(\frac{7}{15}+\frac{11}{12}\right)x\frac{4}{9}\)
= \(\frac{83}{60}x\frac{4}{9}\)
= \(\frac{332}{540}\)
C2 \(\frac{7}{15}x\frac{4}{9}+\frac{4}{9}x\frac{11}{12}\)
= \(\frac{28}{135}+\frac{44}{108}\)
= \(\frac{332}{540}\)
Người ta quét vôi bên tronggồm chung quanhvà trần.M