9+3.(-5)=9+(-15)= -6

\(\frac{-2}{15}\)-\(\frac{4}{25}\)=  \(\frac{-10}{75}\)-\(\frac{12}{75}\)= \(\frac{-22}{75}\)

\(\frac{-3}{5}\).  \(\frac{4}{11}\)+\(\frac{-3}{7}\).  \(\frac{7}{11}\)+   \(\frac{-3}{7}\)=  \(\frac{-12}{55}\)+  \(\frac{-21}{77}\)+   \(\frac{-3}{7}\)

                                                                    =   \(\frac{-84}{385}\)+\(\frac{-105}{385}\)+\(\frac{-165}{385}\)

                                                                    =  \(\frac{-354}{385}\)

a) 9+3.(-5) =9-15=-6

b) \(\frac{-2}{15}-\frac{4}{25}=\frac{-2.5}{75}-\frac{4.3}{75}=\frac{-10-12}{75}=\frac{-22}{75}\)

c) \(\frac{-3}{5}.\frac{4}{11}+\frac{-3}{7}.\frac{7}{11}+\frac{-3}{7}=\frac{-12}{55}+\frac{-21}{77}+\frac{-3}{7}=\frac{-12.7}{385}+\frac{-21.5}{385}+\frac{-21.55}{385}=\frac{-84-105-1155}{385}=\frac{-1344}{385}=\frac{-192}{5}\)

hi! hi! hk bit dug hk :)

a)  \(A=\left(-1\right).\left(-1\right)^2.\left(-1\right)^3.\left(-1\right)^4.....\left(-1\right)^{2016}.\left(-1\right)^{2017}\)

\(=\left[\left(-1\right).\left(-1\right)^3.\left(-1\right)^5.....\left(-1\right)^{2017}\right].\left[\left(-1\right)^2.\left(-1\right)^4.....\left(-1\right)^{2016}\right]\)

TỪ 1 ĐẾN 2017 CÓ 1009 SỐ LẺ NÊN

\(\left(-1\right).\left(-1\right)^3....\left(-1\right)^{2017}=\left(-1\right)\)

TÍCH CỦA \(\left(-1\right)^2.\left(-1\right)^4....\left(-1\right)^{2016}\)LÀ TÍCH CỦA CÁC LŨY THỪA MŨ CHẴN NÊN \(=1\)

\(A=\left(-1\right).1=-1\)

b)  \(\frac{1}{7.7^4.11^2.77^4}.\frac{1}{7^2}.7^8.\left(-11\right)^3.7^{15}.11^{18}\)

\(=\frac{7^8.\left(-11\right)^3.7^{15}.11^{18}}{7.7^4.11^2.7^4.11^4.7^2}\)

\(=\frac{7^{23}.\left(-11\right)^{21}}{7^{11}.11^6}\)

\(=7^{12}.\left(-11\right)^{15}\)

Ta thấy từ 1 đến 2016 là có 2016 số chia thành 1008 là số chẵn nên tích 2016 số đầu là 1 số cuối là -1 nên tích cần tìm là -1

\(11=\frac{77}{7}< \frac{78}{7}\Rightarrow-\frac{11}{3^7\cdot7^3}>-\frac{78}{3^7\cdot7^4}\)

\(\frac{-11}{3^7.7^3}>\frac{-78}{3^7.7^4}\)

`3/7 .4/11+3/7 .7/11-2`

`= 3/7 . ( 4/11 + 7/11)-2`

`= 3/7 . 11/11 -2`

`=3/7 . 1-2`

`= 3/7-2`

`= 3/7 - 14/7`

`=-11/7`

`3/7*4/11+3/7*7/11-2`

`=3/7*(4/11+7/11)-2`

`=3/7*1-2`

`=3/7-2`

`=3/7-14/7`

`=-11/7`

có - 11/3^7.7^3 =-77/3^7.7^4 rồi so sánh với -78/3^7.7^4 nhé :))

ai cứu với ạ

`4/7+4`

`=4/7+4/1`

`=4/7+28/7`

`=32/7`

__

`3+6/11`

`=33/11+6/11`

`=39/11`

__

`3-5/7`

`=3/1-5/7`

`=21/7-5/7`

`=16/7`

__

`21/9-2`

`=21/9-18/9`

`=3/9`

`=1/3`

__

`15/24+2`

`=15/24+48/24`

`=63/24`

`=21/16`

__

`63/45-20/25`

`=63/45-4/5`

`=63/45-36/45`

`=27/45`

`=9/15`

__

`3/4-2/8`

`=3/4-1/4`

`=2/4`

__

`6/7-5/8`

`=48/56-35/56`

`=13/56`

__

`37/45-5/9`

`=37/45-25/45`

`=12/45`

`=4/15`

__

`46/39-11/13`

`=46/39-33/39`

`=13/39`

`=1/2`

__

`5/12+3/4+1/3`

`=5/12+9/12+4/12`

`=14/12+4/12`

`=18/12`

`=3/2`

__

`1/2+3/7+11/14`

`=7/14+6/14+11/14`

`=13/14+11/14`

`=24/14`

`=12/7`

__

`7/10-(1/5+1/4)`

`=7/10-(4/20+5/20)`

`=7/10-9/20`

`=14/20-9/20`

`=5/20`

`=1/4`

__

`15/4-2/3-3/4`

`=(15/4-3/4)-2/3`

`=12/4-2/3`

`=3-2/3`

`=9/3-2/3`

`=7/3`

\(A=\frac{1}{1\cdot2}+\frac{2}{2\cdot4}+\frac{3}{4\cdot7}+\frac{4}{7\cdot11}+...+\frac{10}{46\cdot56}\)

\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+...+\frac{1}{46}-\frac{1}{56}\)

\(A=1-\frac{1}{56}\)

\(A=\frac{55}{56}\)

\(B=\frac{4}{3\cdot7}+\frac{4}{7\cdot11}+\frac{4}{11\cdot15}+...+\frac{4}{23\cdot27}\)

\(B=\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{15}+...+\frac{1}{23}-\frac{1}{27}\)

\(B=\frac{1}{3}-\frac{1}{27}\)

\(B=\frac{8}{27}\)

\(C=\frac{4}{3\cdot6}+\frac{4}{6\cdot9}+\frac{4}{9\cdot12}+...+\frac{4}{99\cdot102}\)

\(C=\frac{4}{3}\left(\frac{3}{3\cdot6}+\frac{3}{6\cdot9}+\frac{3}{9\cdot12}+...+\frac{3}{99\cdot102}\right)\)

\(C=\frac{4}{3}\left(\frac{1}{3}-\frac{1}{6}+\frac{1}{6}-\frac{1}{9}+\frac{1}{9}-\frac{1}{12}+...+\frac{1}{99}-\frac{1}{102}\right)\)

\(C=\frac{4}{3}\left(\frac{1}{3}-\frac{1}{102}\right)\)

\(C=\frac{4}{3}\cdot\frac{33}{102}\)

\(C=\frac{22}{51}\)

Các bạn giải giúp mình nha😐