Nếu 1/3 + 1/6 +1/10 + ...... + 1/x.(x+1) : 2 = 2019/2021
A.x = 2019/2020 B. x = 2019 C. x = 2020 D. x = 2021
2019 x 2020 - 1/ 2019 x 2020 và 2020 x 2021 - 1/ 2020 x 2021
so sánh phân số
Bài 1: thực hiện phép tính
a)1/1×2+1/2×3+1/3×4+...+1/2019×2020
b)1/1×3+1/3×5+1/5×7+...+1/2017×2019
c)3^0+3^1+3^2+...+3^100
d)1/2+1/2^2+1/2^3+...+1/2^2019
Bài2:tìm x
a)|x-2|+|x2 -4=0
b)x+1/2.x-25%.x=10
c)2+4+6+8+...+2x=210
d)1/5×8+1/8×11+1/11×14+...+1/x(x+3)=101/1504
Chú ý: dấu chấm ở câu b)bài 2 là dấu nhân
Tim x biet
\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}=\frac{2019}{2020}\)
x+1/2018+x+1/2019+x+1/2020
x+1/2018+x+1/2019+x+1/2020=0
Tìm x thuộc N biết :
a, ( x- 1 )^3 - 1 = 0
b, ( x - 4 )^2019 = 1
c, ( x - 2019 )^2020 = 0
d, ( x - 1 )^2 = ( x - 1)^3
\(\dfrac{x+1}{2021}\) + \(\dfrac{x+2}{2020}\) + \(\dfrac{x+1}{2019}\) = -3
x-4/2022+x-3/2021+x-2/2020+x-1/2019=-4
