2 : \(\dfrac{2}{7}\)+\(\dfrac{12}{5}\) ; \(\dfrac{5}{16}\) : [\(\dfrac{5}{8}\)+\(\dfrac{3}{24}\)]
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\(a,=\dfrac{5}{7}-\dfrac{33}{8}=-\dfrac{191}{56}\\ b,=\left(\dfrac{12}{17}+\dfrac{5}{17}\right)+\left(\dfrac{19}{7}+\dfrac{3}{7}\right)=1+3=4\\ c,=\left(0,125\cdot8\right)^{12}-\left(\dfrac{45}{15}\right)^3=1-3^3=-26\\ d,=\left(-\dfrac{1}{3}\right)\left(5\dfrac{2}{7}-2\dfrac{2}{7}\right)=-\dfrac{1}{3}\cdot3=-1\\ e,=\dfrac{3^4\cdot3^6}{3^9}=3\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a: =4/5+1/5+2/3+1/3=1+1=2
b: =17/12+7/12+29/7-8/7=3+2=5
c: =3/5+2/5+16/7-1/7-1/7
=1+2=3
d: =2/5+3/5+2/3+1/3+7/4+1/4
=1+1+2
=4
![](https://rs.olm.vn/images/avt/0.png?1311)
b: \(=\dfrac{2}{5}+\dfrac{3}{5}:\dfrac{9-10}{15}-\dfrac{7}{2}\)
\(=\dfrac{4-35}{10}+\dfrac{3}{5}\cdot\dfrac{15}{-1}\)
\(=\dfrac{-31}{10}-9=\dfrac{-31}{10}-\dfrac{90}{10}=-\dfrac{121}{10}\)
c: \(=\dfrac{48-5}{12}\cdot\dfrac{1}{3}+\dfrac{7}{36}=\dfrac{43}{36}+\dfrac{7}{36}=\dfrac{50}{36}=\dfrac{25}{18}\)
d: \(=\dfrac{17}{6}:\dfrac{6}{5}+\dfrac{-7}{12}\)
\(=\dfrac{85}{36}-\dfrac{7}{12}=\dfrac{85}{36}-\dfrac{21}{36}=\dfrac{64}{36}=\dfrac{16}{9}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
`3/5 : x =1/3 +1/2`
` 3/5 : x= 2/6 +3/6`
` 3/5 : x= 5/6`
` x= 3/5 : 5/6`
` x= 3/5 xx 6/5`
` x= 18/25`
__
`x: 7/15 =2`
` x= 2xx 7/15`
` x= 14/15`
__
`x-3/2=11/4-5/4`
`x-3/2= 6/4`
`x= 3/2 +3/2`
`x= 6/2`
`x=3`
__
`x+5/4 = 3/2+7/12`
`x+5/4 = 18/12+7/12`
`x+5/4 = 25/12`
`x= 25/12-5/4`
`x= 25/12- 15/12`
`x= 10/12`
`x= 5/6`
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{7}{12}>\dfrac{5}{12}\) (Vì tử số 7>5; phân số cùng mẫu số)
\(\dfrac{2}{5}=\dfrac{2.3}{5.3}=\dfrac{6}{15}\) -> Điền dấu "="
\(\dfrac{7}{10}< \dfrac{7}{9}\) (Vì phân số cùng tử, phân số nào có mẫu số lớn hơn thì phân số đó bé hơn. Ta có: 10>9 => 7/10 < 7/9)
\(\dfrac{7}{12}>\dfrac{5}{12}\)
\(\dfrac{2}{5}=\dfrac{6}{15}\)
\(\dfrac{7}{10}< \dfrac{7}{9}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{-12}{15}+\dfrac{-4}{26}=\dfrac{-4}{5}+\dfrac{-2}{13}=\dfrac{-52-10}{65}=\dfrac{-62}{65}\)
b) \(5\dfrac{1}{3}-2\dfrac{4}{5}=\dfrac{16}{3}-\dfrac{14}{5}=\dfrac{80}{15}-\dfrac{42}{15}=\dfrac{38}{15}\)
c) \(\dfrac{4}{5}-\left(-\dfrac{2}{7}\right)+\dfrac{-5}{10}=\dfrac{4}{5}+\dfrac{2}{7}-\dfrac{1}{2}=\dfrac{56}{70}+\dfrac{20}{70}-\dfrac{35}{70}=\dfrac{41}{70}\)
d) \(-1\dfrac{2}{7}+\dfrac{3}{14}-\dfrac{5}{21}=\dfrac{-9}{7}+\dfrac{3}{14}-\dfrac{5}{21}=\dfrac{-54}{42}+\dfrac{9}{42}-\dfrac{10}{42}=\dfrac{-55}{42}\)
e) \(12-\dfrac{11}{121}+\left(\dfrac{-8}{9}\right)-\left(-\dfrac{3}{7}\right)\)
\(=12-\dfrac{11}{121}-\dfrac{8}{9}+\dfrac{3}{7}\)
\(=\dfrac{91476}{7623}-\dfrac{693}{7623}-\dfrac{6776}{7623}+\dfrac{3267}{7623}\)
\(=\dfrac{7934}{693}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(d,-\dfrac{5}{12}+\dfrac{3}{4}=-\dfrac{5}{12}+\dfrac{9}{12}=\dfrac{4}{12}=\dfrac{1}{3}\)
\(e,\dfrac{5}{7}.\dfrac{25}{2}-\dfrac{5}{7}.\dfrac{11}{2}=\dfrac{5}{7}.\left(\dfrac{25}{2}-\dfrac{11}{2}\right)=\dfrac{5}{7}.7=5\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(=\left(12+\dfrac{3}{5}\right)\cdot\dfrac{-7}{5}+\left(2+\dfrac{2}{5}\right)\cdot\dfrac{-7}{5}\)
=-7/5(12+3/5+2+2/5)
=-15*7/5=-21
![](https://rs.olm.vn/images/avt/0.png?1311)
1) âm năm phần 12
2) âm mười bảy phần 9
3) -1
Đây là đáp án còn làm bài từ làm nhé
\(2:\dfrac{2}{7}+\dfrac{12}{5}=2.\dfrac{7}{2}+\dfrac{12}{5}=7+\dfrac{12}{5}=\dfrac{47}{5}\)
\(\dfrac{5}{16}:\left[\dfrac{5}{8}+\dfrac{3}{24}\right]=\dfrac{5}{16}:\dfrac{3}{4}=\dfrac{5}{16}.\dfrac{4}{3}=\dfrac{5}{12}\)
\(2:\dfrac{2}{7}+\dfrac{12}{5}=7\dfrac{12}{5}=\dfrac{47}{5}\)
\(\dfrac{5}{16}:\left(\dfrac{5}{8}+\dfrac{3}{24}\right)=\dfrac{5}{16}:\dfrac{3}{4}=\dfrac{5}{16}\cdot\dfrac{4}{3}=\dfrac{20}{48}=\dfrac{5}{12}\)