=(x+x+...+x)+(1+2+...+100)=5750
=100x+5050=5750
100x=5750-5050
100x=700
x=700/100=7
(x+1)+(x+2)+....+(x+100)=5750
x+1+x+2+...+x+100 =5750
\(x\)x100+1+2+...+100 =5750
bí hihi
tự làm nha
( x + 1 ) + ( x + 2 ) + ... + ( x + 100 ) = 5750
x \(\times\) 100 + 1 + 2 + ... + 100 = 5750
x \(\times\) 100 + 5050 = 5750
x \(\times\) 100 = 700
x = 7
=[xx100]+[1+2+....+100]=5750
xx100 =5750-1-2-.....-100
xx100 =700
x =700:100
x =7