1/2×x+2/3×x−1=3 1/3

giup mik luon voi a

LX

bai 5 : tinh 

a) tim x , biet (x+1) +(x+2 ) + ...+(x+100)=5750

b) chung minh rang B = 1/2^2 + 1/3^2 + 1/4^2 + ...+1/2021^2 < 1

giup mik luon voi

so sanh 2 phan so 

A = 10^2020+1/10^2021+1

B = 10^2021+1/10^2022+1

giup mik luon voi a  

thank