Rut Gon B=\(\frac{5^{13}\cdot7^{18}+5^{14}\cdot7^{17}}{5^{13}\cdot7^{17}}\)
Những câu hỏi liên quan
\(\frac{7}{3\cdot4}-\frac{9}{4\cdot5}+\frac{11}{5\cdot6}-\frac{13}{6\cdot7}+\frac{15}{7\cdot8}-\frac{17}{8\cdot9}+\frac{19}{9\cdot10}\)
ta có:(3+4)/4=3/(3*4)+4/(3*4) =1/4+1/3 chứng minh tương tự,cộng vế với vế, ta được kết quả là 13/30
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Tính (theo mẫu)Mẫu:frac{5cdot6cdot7cdot9}{12cdot7cdot27}frac{5cdot6cdot7cdot9}{6cdot2cdot7cdot9cdot3}frac{5}{6}a.frac{3cdot4cdot7}{12cdot8cdot9}.........................................................................b.frac{4cdot5cdot6}{12cdot10cdot8}.......................................................................cfrac{5cdot6cdot7}{12cdot14cdot15}......................................................................
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Tính (theo mẫu)
Mẫu:\(\frac{5\cdot6\cdot7\cdot9}{12\cdot7\cdot27}\)=\(\frac{5\cdot6\cdot7\cdot9}{6\cdot2\cdot7\cdot9\cdot3}\)=\(\frac{5}{6}\)
a.\(\frac{3\cdot4\cdot7}{12\cdot8\cdot9}\)=.........................................................................
b.\(\frac{4\cdot5\cdot6}{12\cdot10\cdot8}\)=.......................................................................
c\(\frac{5\cdot6\cdot7}{12\cdot14\cdot15}\)=......................................................................
a.\(\frac{3\cdot4\cdot7}{12\cdot8\cdot9}\)= \(\frac{3\cdot4\cdot7}{3\cdot4\cdot8\cdot9}\)= \(\frac{7}{72}\)
b. \(\frac{4\cdot5\cdot6}{12\cdot10\cdot8}\)= \(\frac{4\cdot5\cdot2\cdot3}{3\cdot4\cdot5\cdot2\cdot8}\)= \(\frac{1}{8}\)
c.\(\frac{5\cdot6\cdot7}{12\cdot14\cdot15}\)= \(\frac{5\cdot6\cdot7}{2\cdot6\cdot2\cdot7\cdot3\cdot5}\)= \(\frac{1}{12}\)
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mấy bạn olm giúp mình với mình đng cần gấp đúng mình tick cho nha mấy bạn
thực hiện
1) 5/2-1/3+1/4
2)2/5-0,4+\(3\frac{1}{2}\)
3) (3/4-4):(1/2+1/8)
17/13:8/17+7/13 *5/17
\(\frac{1}{3\cdot5}\)+\(\frac{1}{5\cdot7}..............+\frac{1}{91\cdot93}\)
Tính (theo mẫu)Mẫu:frac{5cdot6cdot7cdot9}{12cdot7cdot27}frac{5cdot6cdot7cdot9}{6cdot2cdot7cdot9cdot3}frac{5}{6}a.frac{3cdot4cdot7}{12cdot8cdot9}.............................................b.frac{4cdot5cdot6}{12cdot10cdot8}...........................................c.frac{5cdot6cdot7}{12cdot14cdot15}........................................(Lưu ý:Dấu chấm là dấu nhân)
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Tính (theo mẫu)
Mẫu:\(\frac{5\cdot6\cdot7\cdot9}{12\cdot7\cdot27}\)=\(\frac{5\cdot6\cdot7\cdot9}{6\cdot2\cdot7\cdot9\cdot3}\)=\(\frac{5}{6}\)
a.\(\frac{3\cdot4\cdot7}{12\cdot8\cdot9}\).............................................
b.\(\frac{4\cdot5\cdot6}{12\cdot10\cdot8}\)...........................................
c.\(\frac{5\cdot6\cdot7}{12\cdot14\cdot15}\)........................................
(Lưu ý:Dấu chấm là dấu nhân)
a, \(\frac{3.4.7}{12.8.9}\)= \(\frac{3.4.7}{3.4.8.9}\)= \(\frac{7}{72}\)
b, \(\frac{4.5.6}{12.10.8}\)= \(\frac{4.5.6}{3.4.2.5.8}\)= \(\frac{1}{8}\)
c, \(\frac{5.6.7}{12.14.15}\)= \(\frac{5.6.7}{2.6.2.7.3.5}\)= \(\frac{1}{12}\)
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thực hiện
\(\frac{5}{2}-\frac{1}{3}+\frac{1}{4}\)
\(\frac{2}{5}-0,4+3\frac{1}{2}\)
\(\left(\frac{3}{4}-4\right):\left(\frac{1}{2}+\frac{1}{8}\right)\)
\(\frac{7}{13}:\frac{8}{17}+\frac{7}{13}\cdot\frac{5}{17}\)
\(\frac{1}{3\cdot5}+\frac{1}{5\cdot7}....................+\frac{1}{91\cdot93}\)
\(\frac{5}{2}-\frac{1}{3}+\frac{1}{4}\)
\(\frac{2}{5}-0,4+3\frac{1}{2}\)
\(\left(\frac{3}{4}-4\right):\left(\frac{1}{2}+\frac{1}{8}\right)\)
\(\frac{7}{13}:\frac{8}{17}+\frac{7}{13}\cdot\frac{5}{17}\)
\(\frac{1}{3\cdot5}+\frac{1}{5\cdot7}............+\frac{1}{91\cdot93}\)
Chứng minh rằng :
a) \(7^{11}\cdot7^{13}\cdot7^{17}⋮49\)
b) \(4+3+3^2+3^3+...+3^{200}⋮13;2\)
c) \(1+2^2+2^4+...+2^{98}+2^{100}⋮21\)
d) \(5+5^2+5^3+...+5^{2004}⋮6;31\)
e) \(2+2^2+2^3+...+2^{120}⋮7;31;5\)
Mình làm bài a thôi nhé:
a)7^11 x 7^13 x 7^17= 7^11+13+17=7^41=>7^2 x 7^39=>49 x 7^39
=>49 x7^39 chia hết cho 49
k mình nhé
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Tính bằng cách hợp lý (nếu có thể) :
A = \(\frac{6}{2\cdot2}+\frac{5}{2\cdot13}+\frac{3}{13\cdot4}+\frac{2}{4\cdot18}+\frac{10}{18\cdot7}\)
\(\Rightarrow A=4.\left[\frac{6}{2.\left(2.4\right)}+\frac{5}{\left(2.4\right).13}+\frac{3}{13.\left(4.4\right)}+\frac{2}{\left(4.4\right).18}+\frac{10}{18.\left(7.4\right)}\right]\)
\(=4.\left(\frac{6}{2.8}+\frac{5}{8.13}+\frac{3}{13.16}+\frac{2}{16.18}+\frac{10}{18.28}\right)=4.\left(\frac{1}{2}-\frac{1}{8}+\frac{1}{8}-\frac{1}{13}+\frac{1}{13}-\frac{1}{16}+\frac{1}{16}-\frac{1}{18}+\frac{1}{18}-\frac{1}{28}\right)\)
\(=4.\left(\frac{1}{2}-\frac{1}{28}\right)=4.\frac{13}{28}=\frac{13}{7}\)
B =\(\frac{2^{12}\cdot3^5-4^6\cdot9^2}{\left(2^2\cdot3\right)^6+8^4\cdot3^5}\) - \(\frac{5^{10}\cdot7^3-25^5\cdot49^2}{\left(125\cdot7\right)^3+5^9+14^3}\)
\(B=\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\frac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)
\(B=\frac{2^{12}.3^6-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}-\frac{5^{10}.7^3-5^{10}.7^4}{5^9.7^3+5^9.2^3.7^3}\)
\(B=\frac{2^{12}.3^4.\left(3^2-1\right)}{2^{12}.3^5.\left(3-1\right)}-\frac{5^{10}.7^3.\left(1-7\right)}{5^9.7^3.\left(1+2^3\right)}\)
\(B=\frac{8}{6}-\frac{5-35}{9}\)
\(B=\frac{4}{3}+\frac{30}{9}\)
\(B=\frac{4}{3}+\frac{10}{3}\)
\(B=\frac{14}{3}\)
vậy \(B=\frac{14}{3}\)
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