(x+2)+(x+4)+(x+6)+...+(x+100) = 2700
=> 50x + (2+4+6+...+100) = 2700
=> 50x + 2550 = 2700
=> 50x = 2700 - 2550
=> 50x = 150
=> x = 3
(x+2)+(x+4)+(x+6)+...+(x+100)=2700
>50x+(2+4+6+...+100) =2700
>50x+2550 =2700
>50x =2700-2550
> 50x =150
> x =150:50
>x =3
Vậy X=3 thì (x+2)+(x+4)+(x+6)+...+(x+100) =2700
=>(x+x+x+...+x)+(2+4+6+...+100)=2700
=>50x+\(\frac{102.50}{2}\)=2700
=>50x+51.50=2700
=>50(x+51)=2700
=>x+51=54
=>x=3