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![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=\frac{1}{10}-\frac{1}{13}+\frac{1}{13}-\frac{1}{16}+\frac{1}{16}-\frac{1}{19}+...+\frac{1}{58}-\frac{1}{61}\)
\(A=\frac{1}{10}-\frac{1}{61}=\frac{51}{610}\)
A=3/10.13 +3/13.16+ 3/16.19+....+3/58.61
A=1/10.13+1/13.16+1/16.19+.....+1/58.61
A=1/10- 1/13+ 1/13- 1/16+ 1/16- 1/19+...+1/58 –1/61
A=1/10 – 1/61
A= 61/610 – 10/610
A= 51/610
Mình giải xong rồi k nhá?
![](https://rs.olm.vn/images/avt/0.png?1311)
a/7/9(1/4+3/4)=7/9.1=7/9
b/13/9(16/5-14/5+3/5)=13/9.1=13/9
34cm=34/100m
524mm=524/1000m
70mm=70/1000=7/100m
a/7/9(1/4+3/4)=7/9.1=7/9
b/13/9(16/5-14/5+3/5)=13/9.1=13/9
34cm=34/100m
524mm=524/1000m
70mm=70/1000=7/100m
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(4\frac{3}{x}=\frac{47}{x}\)
=) \(\frac{4x+3}{x}=\frac{47}{x}\)
=) \(4x+3=47\)
=) \(4x=47-3=44\)
=) \(x=44:4=11\)
b) \(x\frac{x}{15}=\frac{112}{5}\)
=) \(\frac{15x+x}{15}=\frac{336}{15}\)
=) \(15x+x=336\)
=) \(16x=336\)
=) \(x=336:16=21\)
Ta có : \(4\frac{3}{x}=\frac{4x+3}{x}=\frac{47}{x}\)
=> 4x + 3 = 47
=> 4x = 44
=> x = 11
![](https://rs.olm.vn/images/avt/0.png?1311)
cai bai nay minh thay
quen quen nhung lai ko nghi ra
chu!
chuc bn hoc gioi1
Ta có : \(\frac{1}{1000}+\frac{13}{1000}+\frac{25}{1000}+.....+\frac{85}{1000}+\frac{97}{1000}\)
\(=\frac{1+13+25+......+85+97}{1000}\)
\(=\frac{441}{1000}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
mình không biết nữa bằng bao nhiêu ấy nhỉ .......? .......? Sory ^.^
1/3 + 13/15 + 33/35 + 61/63 + 97/99
= 45/11 ( mình không tiện giải, để khi khác giải sau)
Chúc bạn may mắn!
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài giải
\(1\frac{1}{3}\text{ x }2\frac{1}{4}\text{ x }\text{ }3\frac{1}{5}\text{ x }4\frac{1}{6}\text{ x }5\frac{1}{7}\text{ x }6\frac{1}{8}\text{ x }7\frac{1}{9}\text{ x }8\frac{1}{10}\)
\(=\frac{4}{3}\text{ x }\frac{9}{4}\text{ x }\frac{16}{5}\text{ x }\frac{25}{6}\text{ x }\frac{36}{7}\text{ x }\frac{49}{8}\text{ x }\frac{64}{9}\text{ x }\frac{81}{10}\)
\(=\frac{4\text{ x }9\text{ x }16\text{ x }25\text{ x }36\text{ x }49\text{ x }64\text{ x }81}{3\text{ x }4\text{ x }5\text{ x }6\text{ x }7\text{ x }8\text{ x }9}\)
\(=\frac{4\text{ x }3^2\text{ x }4^2\text{ x }5^2\text{ x }6^2\text{ x }7^2\text{ x }8^2\text{ x }9^2}{3\text{ x }4\text{ x }5\text{ x }6\text{ x }7\text{ x }8\text{ x }9}\) ( Nếu bạn chưa học lũy thừa thì bạn không cần viết bước này )
\(=4\text{ x }3\text{ x }4\text{ x }5\text{ x }6\text{ x }7\text{ x }8\text{ x }9\)
\(=725760\)
Bài giải
\(1\frac{1}{3}\text{ x }2\frac{1}{4}\text{ x }\text{ }3\frac{1}{5}\text{ x }4\frac{1}{6}\text{ x }5\frac{1}{7}\text{ x }6\frac{1}{8}\text{ x }7\frac{1}{9}\text{ x }8\frac{1}{10}\)
\(=\frac{4}{3}\text{ x }\frac{9}{4}\text{ x }\frac{16}{5}\text{ x }\frac{25}{6}\text{ x }\frac{36}{7}\text{ x }\frac{49}{8}\text{ x }\frac{64}{9}\text{ x }\frac{81}{10}\)
\(=\frac{4\text{ x }9\text{ x }16\text{ x }25\text{ x }36\text{ x }49\text{ x }64\text{ x }81}{3\text{ x }4\text{ x }5\text{ x }6\text{ x }7\text{ x }8\text{ x }9}\)
\(=\frac{4\text{ x }3^2\text{ x }4^2\text{ x }5^2\text{ x }6^2\text{ x }7^2\text{ x }8^2\text{ x }9^2}{3\text{ x }4\text{ x }5\text{ x }6\text{ x }7\text{ x }8\text{ x }9}\) ( Nếu bạn chưa học lũy thừa thì bạn không cần viết bước này )
\(=4\text{ x }3\text{ x }4\text{ x }5\text{ x }6\text{ x }7\text{ x }8\text{ x }9\)
\(=725760\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{2}{5}\)= \(\dfrac{6}{15}\)> \(\dfrac{6}{16}\) = \(\dfrac{3}{8}\) > \(\dfrac{3}{9}\) = \(\dfrac{1}{3}\) = \(\dfrac{1\times5}{3\times5}\) = \(\dfrac{5}{15}\) > \(\dfrac{5}{16}\) vậy \(\dfrac{2}{5}\) > \(\dfrac{3}{8}\) > \(\dfrac{1}{3}\) > \(\dfrac{5}{16}\)
\(\dfrac{5}{16}\) = \(\dfrac{5\times4}{16\times4}\) = \(\dfrac{20}{64}\) > \(\dfrac{20}{65}\) = \(\dfrac{4}{13}\)
Các phân số đã cho được sắp xếp theo thứ tự tăng dần là:
\(\dfrac{4}{13}\); \(\dfrac{5}{16}\); \(\dfrac{1}{3}\); \(\dfrac{3}{8}\); \(\dfrac{2}{5}\)
Ta có ; \(\frac{5}{2\times1}+\frac{4}{1\times11}+\frac{3}{11\times2}+\frac{1}{2\times15}+\frac{13}{15\times4}\)
\(=\frac{8}{2\times11}+\frac{3}{11\times2}+\frac{2}{4\times15}+\frac{13}{15\times4}+\frac{5}{2}\)
\(=\frac{11}{11\times2}+\frac{15}{15\times4}+\frac{5}{2}\)
\(=\frac{1}{2}+\frac{1}{4}+\frac{5}{2}\)
\(=\frac{2}{4}+\frac{1}{4}+\frac{10}{4}\)
\(=\frac{13}{4}\)
dễ
bây h tui gợi ý là nó nhân thêm 7
xog r đó