\(X+1+X+2+X+3+...+X+100=5750.\)
\(\left(X+1\right)+\left(X+2\right)+\left(X+3\right)+...+\left(X+100\right)=5750.\)
\(\Leftrightarrow\left(X+X+X+...+X\right)+\left(1+2+3+...+100\right)=5750.\)
\(100X+5050=5750\)
\(100X=5750-5050=700\)
\(X=700:100=7\)
(x+1)+(x+2)+(x+3)+........+(x+100)=5750
(x+x+...+x)+(1+2+3+...+100)=5750
(x.100)+(1+100).100:2=5750
(x.100)+5050=5750
x.100=5750-5050
x.100=700
x =700:100
x = 7
Vậy x=7