Ta có : (x+1) +(x+2) +......+(x+100)=5750
\(\Leftrightarrow\) 100.x +(1+2+...+100) =5750
\(\Leftrightarrow\) 100.x +5050 =5750
\(\Leftrightarrow\) 100x =5750-5050
\(\Leftrightarrow\) 100.x =700
\(\Leftrightarrow\)x=700: 100
\(\Leftrightarrow\) x =7
Vậy x=7
Có 100 nhóm nên có 100 số x
(x+x+...+x)+(1+2+3+4+...+100)=5750
x.100 + 5050=5750
x.100=5750-5050
x.100=700
x=700:100
x=7
( x + 1 ) + ( x + 2 ) + ... + ( x + 100 ) = 5750
( x x + x + x + ... + x ) + ( 1 + 2 + 3 + 4 + ... + 100 ) = 5750
100x + ( 100 + 1 ) x 100 : 2 = 5750
100x + 101 x 50 = 5750
100x + 5050 = 5750
100x = 5750 - 5050
100x = 700
x = 700 : 100
x = 7
(x+1) + (x+2)+........+(x+100) = 5750
=> ( x + x + x + ... + x ) ( 100 số x ) + ( 1 + 2 + 3 + ... + 100 ) = 5750
=> 100x + [ (100 : 2 ) . ( 100 + 1 ) ] = 5750
=> 100x + [ 50 . 101 ] = 5750
=> 100x + 5050 = 5750
=> 100x = 5750 - 5050
=> 100x = 700
=> x = 700 : 100
=> x = 7
Vậy : x = 7
(x+1)+(x+2)+......+(x+100)=x+1+x+2+........+x+100=100x+(1+2+3+....+100)=\(100x+\frac{101\cdot100}{2}=100x+5050=5750\)
=>100x=5750-5050=700=>x=7
(x+1) + (x+2)+........+(x+100) = 5750
=>x+1+x+2+..........+x+100=5750
=>x+x+...+x+1+2+....100 <chú ý: có 100 số x>
=>100x+5050=5750
=>100x=5750-5050
=>100x=700
=>x=700/100
=>x=7
vậy:x=7
