x + ( x + 2 ) + ( x + 4 ) + ( x + 6 ) + ( x + 8 ) +...........+ ( x + 98 ) + ( x + 100 ) = 2601
= (51x)[\(\left(100+2\right)x\left(\frac{100-2}{2}+1\right):2\)] =2601
đến đây e tự giải nốt nhé!
<=> 51x + (2+4+6+8+...+100)=2601
<=> 51x + 2550 = 2601
<=> 51x = 51
<=> x = 1
Vậy .......
Ta có : x + ( x + 2 ) + ( x + 4 ) + ( x + 6 ) + ... + ( x + 98 ) + ( x + 100 ) = 2601
<=> ( x + x + x + ... + x ) + ( 0 + 2 + 4 + 6 + ... + 98 + 100 ) =2601
<=> 51.x + 2550 = 2601
<=> 51.x = 2601 - 2550
<=> 51.x = 51
<=> x = 1
Vậy x = 1