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`@` `\text {Ans}`
`\downarrow`
`a)`
\(\dfrac{7}{5}\cdot\dfrac{8}{19}+\dfrac{7}{5}\cdot\dfrac{12}{19}-\dfrac{7}{5}\cdot\dfrac{1}{19}\)
`=`\(\dfrac{7}{5}\cdot\left(\dfrac{8}{19}+\dfrac{12}{19}-\dfrac{1}{19}\right)\)
`=`\(\dfrac{7}{5}\cdot\dfrac{19}{19}=\dfrac{7}{5}\cdot1=\dfrac{7}{5}\)
`b)`
\(-\dfrac{3}{5}\cdot\dfrac{5}{7}+\left(-\dfrac{3}{5}\right)\cdot\dfrac{3}{7}+\left(-\dfrac{3}{5}\right)\cdot\dfrac{6}{7}\)
`=`\(-\dfrac{3}{5}\cdot\left(\dfrac{5}{7}+\dfrac{3}{7}+\dfrac{6}{7}\right)\)
`=`\(-\dfrac{3}{5}\cdot\dfrac{14}{7}\)
`=`\(-\dfrac{3}{5}\cdot2=-\dfrac{6}{5}\)
`c)`
\(10\dfrac{2}{9}+\left(2\dfrac{2}{5}-7\dfrac{2}{9}\right)\)
`=`\(10\dfrac{2}{9}+2\dfrac{2}{5}-7\dfrac{2}{9}\)
`=`\(\left(10\dfrac{2}{9}-7\dfrac{2}{9}\right)+2\dfrac{2}{5}\)
`=`\(3+2\dfrac{2}{5}=\dfrac{27}{5}\)
`d)`
\(6\dfrac{3}{10}-\left(3\dfrac{4}{7}+2\dfrac{3}{10}\right)\)
`=`\(6\dfrac{3}{10}-3\dfrac{4}{7}-2\dfrac{3}{10}\)
`=`\(\left(6\dfrac{3}{10}-2\dfrac{3}{10}\right)-3\dfrac{4}{7}\)
`=`\(4-3\dfrac{4}{7}=\dfrac{3}{7}\)
a) \(\dfrac{7}{5}.\dfrac{8}{19}+\dfrac{7}{5}.\dfrac{12}{19}-\dfrac{7}{5}.\dfrac{1}{19}\)
\(=\dfrac{7}{5}.\left(\dfrac{8}{19}+\dfrac{12}{19}-\dfrac{1}{19}\right)\)
\(=\dfrac{7}{5}.1\)
\(=\dfrac{7}{5}\)
b) \(\dfrac{-3}{5}.\dfrac{5}{7}+\dfrac{-3}{5}.\dfrac{3}{7}+\dfrac{-3}{5}.\dfrac{6}{7}\)
\(=\dfrac{-3}{5}.\left(\dfrac{5}{7}+\dfrac{3}{7}+\dfrac{6}{7}\right)\)
\(=\dfrac{-3}{5}.2\)
\(=\dfrac{-6}{5}\)
c) \(10\dfrac{2}{9}+\left(2\dfrac{2}{5}-7\dfrac{2}{9}\right)\)
\(=\dfrac{92}{9}+\dfrac{12}{5}-\dfrac{65}{9}\)
\(=\dfrac{92}{9}-\dfrac{65}{9}+\dfrac{12}{5}\)
\(=3+\dfrac{12}{5}\)
\(=\dfrac{15}{5}+\dfrac{12}{5}\)
\(=\dfrac{27}{5}\)
d) \(6\dfrac{3}{10}-\left(3\dfrac{4}{7}+2\dfrac{3}{10}\right)\)
\(=\dfrac{63}{10}-\dfrac{25}{7}-\dfrac{23}{10}\)
\(=\dfrac{63}{10}-\dfrac{23}{10}-\dfrac{25}{7}\)
\(=4-\dfrac{25}{7}\)
\(=\dfrac{28}{7}-\dfrac{25}{7}\)
\(=\dfrac{3}{7}\)
Chúc bạn học tốt
`@` `\text {Ans}`
`\downarrow`
`(3^5 * 3^7)/(3^11)`
`= (3^(5+7))/(3^11)`
`= (3^12)/(3^11)`
`=3`
\(\dfrac{3^5\cdot3^7}{3^{11}}\)
\(=\dfrac{3^{5+7}}{3^{11}}\)
\(=\dfrac{3^{12}}{3^{11}}\)
\(=3^{12-11}\)
\(=3\)
Sửa đề:
B = 1 - 3 - 5 + 7 + 9 - 11 - 13 + 15 + ... + 2019 - 2021 - 2023 + 2025 + 2027
= (1 - 3 - 5 + 7) + (9 - 11 - 13 + 15) + ... + (2019 - 2021 - 2023 + 2025) + 2027
= 0 + 0 + ... + 0 + 2027
= 2027
Nguyễn Linh Anh, sao bạn tính giỏi thế????????????????????????????????????
1/(6x-32).35=5.37
(6x-9) = 5. 2187
(6x-9) = 10935
6x = 10935 + 9 =10944
x = 10944 : 6 =1824
2/8x-5.23=(5.2)3-53.23
/8x-5.8=1000-125.8
8x -40 = 0
8x = 40
x = 40 : 8 =5
MIK CŨNG HỌC LỚP 6 NHƯNG MIK NGHĨ LÀ MIK CHƯA HỌC BÀI NÀY
Bài làm
Bạn hamlon bên dưới không làm được vậy để mình làm cho bạn .
\(\frac{3}{5}.\frac{3}{7}+\frac{3}{5}.\frac{2}{9}-\frac{3}{5}.\frac{3}{11}\)
\(=\frac{3}{5}\left(\frac{3}{7}+\frac{2}{9}-\frac{3}{11}\right)\)
\(=\frac{3}{5}.\left(\frac{297}{693}+\frac{154}{693}-\frac{189}{693}\right)\)
\(=\frac{3}{5}.\frac{262}{693}\)
\(=\frac{262}{1155}\)