4.5/7
22/23.9/11
-9/7.7/15
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12.3 x 4,5 + 4,5 x 7,7
=4,5 x (12,3 + 7,7 )
=4,5 x 20
=90
12,3 x 4,5 + 4,5 x 77
= (12,3 + 77) x 4,5
= 20 x 4,5
= 90
:))
9+3.(-5)=9+(-15)= -6
\(\frac{-2}{15}\)-\(\frac{4}{25}\)= \(\frac{-10}{75}\)-\(\frac{12}{75}\)= \(\frac{-22}{75}\)
\(\frac{-3}{5}\). \(\frac{4}{11}\)+\(\frac{-3}{7}\). \(\frac{7}{11}\)+ \(\frac{-3}{7}\)= \(\frac{-12}{55}\)+ \(\frac{-21}{77}\)+ \(\frac{-3}{7}\)
= \(\frac{-84}{385}\)+\(\frac{-105}{385}\)+\(\frac{-165}{385}\)
= \(\frac{-354}{385}\)
a) 9+3.(-5) =9-15=-6
b) \(\frac{-2}{15}-\frac{4}{25}=\frac{-2.5}{75}-\frac{4.3}{75}=\frac{-10-12}{75}=\frac{-22}{75}\)
c) \(\frac{-3}{5}.\frac{4}{11}+\frac{-3}{7}.\frac{7}{11}+\frac{-3}{7}=\frac{-12}{55}+\frac{-21}{77}+\frac{-3}{7}=\frac{-12.7}{385}+\frac{-21.5}{385}+\frac{-21.55}{385}=\frac{-84-105-1155}{385}=\frac{-1344}{385}=\frac{-192}{5}\)
hi! hi! hk bit dug hk :)
7/3.4 - 9/4.5 + 11/5.6 - 13/6.7 + 15/7.8 - 17/8.9 + 19/9.10
= 3+4/3.4 - 4+5/4.5 + 5+6/5.6 - 6+7/6.7 + 7+8/7.8 - 8+9/8.9 + 9+10/9.10
=1/3 + 1/4 - 1/4 - 1/5 + 1/5 + 1/6 -1/6 - 1/7 +1/7 +1/8 - 1/8 - 1/9 + 1/9 + 1/10
=1/3 + 1/10=13/30
\(=\frac{6+1}{12}-\frac{10-1}{20}+\frac{10+1}{30}-\frac{14-1}{42}+\frac{14+1}{56}-\frac{18-1}{72}+\frac{18+1}{90}\)
=\(\frac{6}{12}+\frac{1}{12}-\frac{10}{20}+\frac{1}{20}+\frac{10}{30}+\frac{1}{30}-\frac{14}{42}+\frac{1}{42}+\frac{14}{56}+\frac{1}{56}-\frac{18}{72}+\frac{1}{72}+\frac{18}{90}+\frac{1}{90}\)
=\(\frac{1}{2}+\frac{1}{12}-\frac{1}{2}+\frac{1}{20}+\frac{1}{3}+\frac{1}{30}-\frac{1}{3}+\frac{1}{42}+\frac{1}{4}+\frac{1}{56}-\frac{1}{4}+\frac{1}{72}+\frac{1}{5}+\frac{1}{90}\)
\(=\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}+\frac{1}{90}+\frac{1}{5}\)
\(=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}+\frac{1}{9}-\frac{1}{10}+\frac{1}{6}\)
\(=\frac{1}{3}-\frac{1}{10}+\frac{1}{5}\)
\(=\frac{10}{30}-\frac{3}{30}+\frac{6}{30}=\frac{13}{30}\)
`4 . 5/7`
`=20/7`
__
`22/23 . 9/11`
`= 22.9/23.11`
`= 2.9/23.1`
`= 18/23`
__
`-9/7 . 7/15`
`= -9/15`
`= - 3/5`
gần lên đại tá=))