![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a)C1:=2/7:2/5
=5/7
C2:=6/7:2/5-4/7:2/5
=15/7-10/7
=5/7
b)C1:=88/30+77/30
=11/2
C2:=(8/15+7/15):2/11
=1:2/11
=11/2
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) Cách 1:
(6/7 - 4/7):2/5
=2/7 : 2/5
=5/7
Cách 2:
(6/7 - 4/7):2/5
=6/7:2/5 - 4/7:2/5
=15/7-10/7
=5/7
b) Cách 1:
8/15:2/11+7/15:2/11
=44/15+77/30
=165/30=11/2
Cách 2:
8/15:2/11+7/15:2/11
= (8/15+7/15):2/11
=1:2/11
=11/2
![](https://rs.olm.vn/images/avt/0.png?1311)
cách 1 :
\(\frac{3}{5}\chi\frac{7}{9}+\frac{3}{5}\chi\frac{2}{9}\)
= \(\frac{3}{5}\chi\left(\frac{7}{9}+\frac{2}{9}\right)\)
= \(\frac{3}{5}\chi1\)
= \(\frac{3}{5}\)
cách 2 :
\(\frac{3}{5}\chi\frac{7}{9}+\frac{3}{5}\chi\frac{2}{9}\)
= \(\frac{7}{15}\) + \(\frac{2}{15}\)
= \(\frac{9}{15}=\frac{3}{5}\)
\(C1:\frac{3}{5}.\frac{7}{9}+\frac{3}{5}.\frac{2}{9}\) \(C2:\frac{3}{5}.\frac{7}{9}+\frac{3}{5}.\frac{2}{9}\)
\(=\frac{3}{5}\left(\frac{7}{9}+\frac{2}{9}\right)=\frac{3}{5}.1=\frac{3}{5}\) \(=\frac{7}{15}+\frac{2}{15}=\frac{3}{5}\)
\(C1:\frac{8}{15}:\frac{2}{11}+\frac{7}{15}:\frac{2}{11}\) \(C2:\frac{8}{15}:\frac{2}{11}+\frac{7}{15}:\frac{2}{11}\)
\(=\left(\frac{8}{15}+\frac{7}{15}\right):\frac{2}{11}=1:\frac{2}{11}=\frac{11}{2}\) \(=\frac{44}{15}+\frac{77}{30}=\frac{88}{30}+\frac{77}{30}=\frac{11}{2}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
`4/15+35/99+11/15-2/7+64/99-5/7`
`=(4/15+11/15)+(35/99+64/99)-(2/7+5/7)`
`=15/15+99/99-7/7`
`=1+1-1`
`=2-1`
`=1`
![](https://rs.olm.vn/images/avt/0.png?1311)
2/5 + 11/15 = 17/15
7/8 - 7/9 = 7/72
11/13 x 26/31 = 22/31
16/24 : 4 = 1/6
30 : 6/5 = 25
9/16 : 4 = 9/64
1/2 : 1/3 x 8/15 = 3/2 x 8/15 = 4/5
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{2}{1}+\dfrac{12}{56}=\dfrac{112+12}{56}=\dfrac{122}{56}=\dfrac{61}{28}\)
\(\left(\dfrac{8+7}{15}\right):\dfrac{2}{11}\)
\(1:\)\(\dfrac{2}{11}\)
\(\dfrac{11}{2}\)
=(8/15+7/15):2/11
=1:2/11
=11/2
\(\frac{8}{15}:\frac{2}{11}+\frac{7}{15}:\frac{2}{11}\)
\(=\frac{8}{15}\times\frac{11}{2}+\frac{7}{15}\times\frac{11}{2}\)
\(=\frac{11}{2}\times\left(\frac{8}{15}+\frac{7}{15}\right)\)
\(=\frac{11}{2}\times1\)
\(=\frac{11}{2}\)
P/s tham khảo nha