cho a/b=c/d
chứng minh rằng:a-b/a=c-d/c
giúp mình nha help me😀😀😀😀😀😀
K
Khách
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N
8
31 tháng 12 2019
đăng hình là ko biết nha!nếu biết thì dạy đăng cho.
☺️ 😀 😁 😂 🤣 😃 😄 😁 😁 😂 🤣 😃 😄 😅 .
NM
1
S
_silverlining
CTVVIP
19 tháng 4 2017
When I was a student, I used to live in Hanoi.So I was the person who always got traffic jams. Nowadays, althought the traffic in Hanoi has been improved ,it still is one of the most serious problems in our society. In my opinion, there are some following ways to reduce the traffic jams. Firstly, The government should build more motorways because many streets and roads are narrow, a lot of transports share one road so it is easy to cause accidents and traffic jams. Secondly, a law about driving in city center should be given. Motorists driving in city center must be charged strictly. There are too much motocycles in the city, many motorisrs are too young, they don't have driving license, they don't understand the law or they don't obey the law seriously . The government should encourage people to use the puplic transport by discouring the price for someone who always uses public transport, especially for students ,workers, etc, opening more bus routes,maybe build the subway. I think subway is the best way to reduce the traffic jams. Things we should do immedietely are educating people from early age, issueing a law in traffic, banning stricly the person who don't obey the law. In conclusion, we should be aware of disadvantages of traffic jams. It affects on every sides of our life.
7 tháng 7 2020
trả lời:
1996 x 1997 + 1998 x 3 + 1994 / 1997 x 1999 - 1997 x 1997
= 1996 x 1997 + ( 1997 + 1 x 3 ) + 1994 / 1997 x 1999 - 1997 x 1997
= 1996 x 1998 + 1 x 3 + 1994 / 1997 x 1999 - 1997 x 1997
= 3988008 + 3 + 1994 / 1997 x 1999 - 1997 x 1997
= 3990005 / 1997 x 1999 - 1997 x 1997
= 3990005 / ( 1999 - 1997 ) x 1997
= 3990005 / 3994
NC
7 tháng 7 2020
Bài làm:
\(\frac{1997.1996+1998.3+1944}{1994.1999-1997.1994}\)
\(=\frac{1997.1996+\left(1997+1\right).3+1994}{1994.\left(1999-1997\right)}\)
\(=\frac{1997.1996+1997.3+3+1994}{1994.2}\)
\(=\frac{1997.\left(1996+3\right)+1997}{1994.2}\)
\(=\frac{1997.\left(1999+1\right)}{1994.2}\)
\(=\frac{1997.2000}{1994.2}\)
\(=\frac{998500}{997}\)
Hc tốt!
31 tháng 12 2018
8 tế bào nha bạn!
gọi số lần phân chia là n thì số tế bào sau n lần phân chia là \(2^n\)
Đặt \(\frac{a}{b}=\frac{c}{d}=k\Rightarrow a=bk,c=dk\)
Ta có: \(\frac{a-b}{a}=\frac{bk-b}{bk}=\frac{b\left(k-1\right)}{bk}=\frac{k-1}{k}\)(1)
\(\frac{c-d}{c}=\frac{dk-d}{dk}=\frac{d\left(k-1\right)}{dk}=\frac{k-1}{k}\)(2)
Từ (1) và (2) \(\Rightarrow\frac{a-b}{a}=\frac{c-d}{c}\)