(2018 2018.2019 -2018 2018.2018):2018
giúp mik
K
Khách
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Những câu hỏi liên quan
LM
1
KT
17 tháng 1 2018
\(\frac{2017.2018-1}{2017.2018}=1-\frac{1}{2017.2018}\)
\(\frac{2018.2019-1}{2018.2019}=1-\frac{1}{2018.2019}\)
Ta thấy \(2017.2018< 2018.2019\)
nên \(\frac{1}{2017.1018}>\frac{1}{2018.2019}\)
\(\Rightarrow\)\(1-\frac{1}{2017.2018}< 1-\frac{1}{2018.2019}\)
Vậy \(\frac{2017.2018-1}{2017.2018}< \frac{2018.2019-1}{2018.2019}\)
5 tháng 4 2018
(1.2 + 2.3 + 3.4 + ... + 2018.2019) - (12 + 22 + ... + 20182)
= (1.2 + 2.3 + ... + 2018.2019) - (1.1 + 2.2 + ... + 2018.2018)
= (1.2 + 2.3 + ... + 2018.2019) - [1.(2 - 1) + 2.(3 - 1) + ... + 2018.(2019 - 1)]
= (1.2 + 2.3 + ... + 2018.2019) - (1.2 + 2.3 + ... + 2018.2019 - 1 - 2 - 3 - ... - 2018)
= (1.2 + 2.3 + ... + 2018.2019) - [1.2 + 2.3 + ... + 2018.2019 - (1 + 2 + ... + 2018)]
= (1.2 + 2.3 + ... + 2018.2019) - (1.2 + 2.3 + ... + 2018.2019) + (1 + 2 + 3 + ... + 2018)
= 1 + 2 + ... + 2018 (có : (2018 - 1) : 1 + 1 = 2018 (số))
= (2018 + 1).2018 : 2
= 2037171
TS
2
6 tháng 6 2023
\(A=\dfrac{2020}{2019}-\dfrac{2019}{2018}+\dfrac{1}{2018\times2019}\)
\(A=\dfrac{2020}{2019}-\dfrac{2019}{2018}+\dfrac{1}{2018}-\dfrac{1}{2019}\)
\(A=\left(\dfrac{2020}{2019}-\dfrac{1}{2019}\right)-\left(\dfrac{2019}{2018}-\dfrac{1}{2018}\right)\)
\(A=\left(\dfrac{2020-1}{2019}\right)-\left(\dfrac{2019-1}{2018}\right)\)
\(A=1-1\)
\(A=0.\)
6 tháng 6 2023
\(A=\dfrac{2020}{2019}-\dfrac{2019}{2018}+\dfrac{1}{2018\times2019}\)
\(A=\dfrac{2020}{2019}-\dfrac{2019}{2018}+\dfrac{1}{2018}-\dfrac{1}{2019}\)
\(A=\left(\dfrac{2020}{2019}-\dfrac{1}{2019}\right)-\left(\dfrac{2019}{2018}-\dfrac{1}{2018}\right)\)
\(A=\dfrac{2019}{2019}-\dfrac{2018}{2018}\)
\(A=1-1\)
\(A=0\)
SM
3
16 tháng 11 2019
\(x\left(x-2018\right)-2019x+2018.2019=0\)
\(\Leftrightarrow x\left(x-2018\right)-2019x+4074342=0\)
\(\Leftrightarrow x^2-2018x-2019x+4074342=0\)
\(\Leftrightarrow x^2-4073x+4074342=0\)
\(\Leftrightarrow\left(x-2018\right)\left(x-2019\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-2018=0\\x-2019=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=2018\\x=2019\end{cases}}\)
16 tháng 11 2019
X(X-2018) - (2019X - 2018.2019) = 0
<=> X(X-2018) - 2019(X-2018) = 0
<=> X(X-2018). X(X-2019) = 0
\(\orbr{\begin{cases}X-2018=0\\X-2019=0\end{cases}< =>}\orbr{\begin{cases}X=2018\\X=2019\end{cases}}\)
\(\left(20182018\cdot2019-20182018\cdot2018\right):2018\)
\(=20182018\cdot\left(2019-2018\right):2018\)
\(=20182018:2018\)
\(=10001\)
có sai đề ko bạn]