\(\left(x-1\right)+\left(x-2\right)+....+\left(x-100\right)=4950\)
\(\Leftrightarrow\left(x+x+....+x\right)+\left(1+2+...+100\right)=4950\)
\(\Leftrightarrow100x-\frac{\left(100+1\right)\left[\left(100-1\right):1+1\right]}{2}=4950\)
\(\Leftrightarrow100x-5050=4950\)
\(\Leftrightarrow x=100\)
Vậy ...
100x-(1+2+3+....+100)=4950
100x-5050=4950
100x=10000
x=100
(x - 1) + (x - 2) + (x - 3) + ...+ (x - 100) = 4950
X x100-(1+2+3+......+100)=4950
X x100-5050=4950
X x100=4950+5050
X x100=10000
x=10000:100
x=100
\(\left(x-1\right)+\left(x-2\right)+\left(x-3\right)+...+\left(x-100\right)=4950\)
\(\Rightarrow100x-\left(1+2+3+...+100\right)=4950\)
\(\Rightarrow100x-\left[\frac{\left(100+1\right)\times100}{2}\right]=4950\)
\(\Rightarrow100x-5050=4950\)
\(\Rightarrow100x=4950+5050\)
\(\Rightarrow100x=10000\)
\(\Rightarrow x=10000\div100\)
\(\Rightarrow x=100\)
Vậy x = 100
_Chúc bạn học tốt_
