Tìm x, biết: |2019-x|+|2020-x|+|2021-x|=2
Tìm x biết:
( 1/2 + 1/3 + ... + 1/2021 ).x = 2021/1 +2019/2 + ... + 2/2019 + 1/2020
Tìm x biết:
( 1/2 + 1/3 + ... + 1/2021 ).x = 2021/1 +2019/2 + ... + 2/2019 + 1/2020
tìm x,y nguyên biết (x-2019)2000+(x+2020)^2020=2020^y-2021
Tìm chữ số tận cùng của A biết A 1 x 2 x 3 x 4 x ... x 2020 x 2021 1 x 3 x 5 x ... x 2019 x 2021.
Dễ thấy A chia hết cho 10 nên A có tận cùng là 0
còn 1x 3 x 5 x... x 2021 là một số lẻ và chia hết cho 5 nên có tận cùng là 5
Là 1 bạn ơi!!!
1 tìm x biết
x-4/2021+x-3/2020=x-2/2019+x-1/2018
giúp mk vs lm ơn
tìm x,y,z biết :x-y=2019;y-z=-2020;z+x=2021
Ta có: (x-y) + (y-z) + (z+x) = 2019 + (-2020) + 2021
x-y+y-z+z+x=2020
2x = 2020
x = 2020 : 2
x = 1010
Suy ra : y = 1010 - 2019 = -1009
z = 2021 - 1010= 1011
Vậy x= 1010 , y = -1009 , z = 1011
Tìm x biết
\(\frac{x+4}{2019}+\frac{x+3}{2020}=\frac{x+2}{2021}+\frac{x+1}{2022}\)
\(\frac{x+4}{2019}+\frac{x+3}{2020}=\frac{x+2}{2021}+\frac{x+1}{2020}\)
\(\Leftrightarrow(\frac{x+4}{2019}+1)+(\frac{x+3}{2020}+1)=(\frac{x+2}{2021}+1)+(\frac{x+1}{2022}+1)\)
\(\Leftrightarrow\frac{x+2023}{2019}+\frac{x+2023}{2020}=\frac{x+2023}{2021}+\frac{x+2023}{2022}\)
\(\Leftrightarrow\frac{x+2023}{2019}+\frac{x+2023}{2020}-\frac{x+2023}{2021}-\frac{x+2023}{2022}=0\)
\(\Leftrightarrow\left(x+2023\right)\left(\frac{1}{2019}+\frac{1}{2020}-\frac{1}{2021}-\frac{1}{2020}\right)=0\)
\(\Leftrightarrow x+2023=0\)
\(\Leftrightarrow x=-2023\)
Nhầm đề :( Với bước thứ 4 sửa thành ( 1/2019 + 1/2020 - 1/2021 - 1/2022 )
\(\frac{x+4}{2019}+\frac{x+3}{2020}=\frac{x+2}{2021}+\frac{x+1}{2022}\)
\(\Leftrightarrow\)\(\frac{x+4}{2019}+\frac{x+3}{2020}+2=\frac{x+2}{2021}+\frac{x+1}{2022}+2\)
\(\Leftrightarrow\)\(\left(\frac{x+4}{2019}+1\right)+\left(\frac{x+3}{2020}+1\right)=\left(\frac{x+2}{2021}+1\right)+\left(\frac{x+1}{2022}+1\right)\)
\(\Leftrightarrow\)\(\left(\frac{x+4}{2019}+\frac{2019}{2019}\right)+\left(\frac{x+3}{2020}+\frac{2020}{2020}\right)\)\(=\)\(\left(\frac{x+2}{2021}+\frac{2021}{2021}\right)+\left(\frac{x+1}{2022}+\frac{2022}{2022}\right)\)
\(\Leftrightarrow\)\(\frac{x+2023}{2019}+\frac{x+2023}{2020}=\frac{x+2023}{2021}+\frac{2023}{2022}\)
\(\Leftrightarrow\)\(\frac{x+2023}{2019}+\frac{x+2023}{2020}-\frac{x+2023}{2021}-\frac{x+2023}{2022}=0\)
\(\Leftrightarrow\) \(\left(x+2023\right).\left(\frac{1}{2019}+\frac{1}{2020}-\frac{1}{2021}-\frac{1}{2022}\right)=0\)
\(\Leftrightarrow\)\(x+2023=0\) ( Vì \(\frac{1}{2019}+\frac{1}{2020}-\frac{1}{2021}-\frac{1}{2022}\ne0\))
\(\Leftrightarrow\)\(x=-2023\)
Vậy x = -2023
2019 x 2020 - 1/ 2019 x 2020 và 2020 x 2021 - 1/ 2020 x 2021
so sánh phân số
Tìm x bt:
\(\dfrac{x+1}{2021}+\dfrac{x+2}{2020}+\dfrac{x+3}{2019}\)