\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+50\right)=1325\)
\(\Leftrightarrow50x+\left(1+2+3+...+50\right)=1325\)
\(\Leftrightarrow50x+\frac{50.\left(50+1\right)}{2}=1325\)
\(\Leftrightarrow50x+1275=1325\)
\(\Leftrightarrow50x=50\)
\(\Leftrightarrow x=1\)
Vậy x =1
Tính tổng: 1 + 2+ 3 +... +50 = (50 + 1).50 : 2 = 1275
( x +1 ) + ( x + 2 ) + ( x + 3 ) + ... + ( x + 50 ) = 1325
( chú ý vế trái của 50 hạng tử )
( x + x + x +... + x ) + ( 1+ 2 + 3 +...+ 50 ) =1325
50 . x + 1275 =1325
50 . x = 1325 - 1275
50 . x = 50
x = 1