1 ) 5/4 + 1/6 : 7/9
= 5/4 + 1/6 . 9/7
= 5/4 + 1 . 9 / 6 . 7
= 5/4 + 3/14
= 35/28 + 6/28
= 41/28
#Cothanhkhe
2) -1,6 : ( 1 + 2/3 )
= -16/10 : ( 3/3 + 2/3 )
= -8/5 : 3 + 2 /3
= -8/5 : 5/3
= -8/5 . 3/5
= -8 . 3 / 5 . 5
= -24/25
#Cothanhkhe
1)\(\frac{5}{4}+\frac{1}{6}:\frac{7}{9}\)
\(=\frac{5}{4}+\frac{1}{6}.\frac{9}{7}\)
\(=\frac{5}{4}+\frac{3}{14}\)
\(=\frac{30}{24}+\frac{6}{24}\)
\(=\frac{36}{24}=\frac{3}{2}\)
2)\(-1,6:\left(1+\frac{2}{3}\right)\)
\(=\frac{-16}{10}:\left(\frac{3}{3}+\frac{2}{3}\right)\)
\(=\frac{-8}{5}:\frac{5}{3}\)
\(=\frac{-8}{5}.\frac{3}{5}\)
\(=\frac{-24}{25}\)
3) \(1,4.\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right):2\frac{1}{5}\)
\(=\frac{14}{10}.\frac{15}{49}-\left(\frac{12}{15}+\frac{10}{15}\right):\frac{11}{5}\)
\(=\frac{21}{49}-\frac{22}{15}:\frac{11}{5}\)
\(=\frac{21}{49}-\frac{22}{15}.\frac{5}{11}\)
\(=\frac{21}{49}-\frac{2}{3}\)
\(=\frac{63}{147}-\frac{98}{147}\)
\(=\frac{35}{147}\)
k giúp mik ✅
