Question

Tìm x :

(x+1)+(x+2)+(x+3)+...+(x+2013)=20132014

Answer 1

\((x+1)+(x+2)+(x+3)+...+(x+2013)=20132014\)

\(x+1+x+2+x+3+...+x+2013=20132014\)

\(2013x+(1+2+3+...+2013)=20132014\)

\(2013x+\dfrac{2013\left(2013+1\right)}{2}=20132014\)

\(2013x+2027091=20132014\)

\(2013x=20132014-2027091\)

\(2013x=18104923\)

\(x=18104923:2013\)

\(x=8994\)(kq đã làm tròn)

Answer 2

Ta có : \(\left(x+1\right)+\left(x+2\right)+...+\left(x+2013\right)=20132014\)

\(\Leftrightarrow\left(x+x+...+x\right)+\left(1+2+...+2013\right)=20132014\)

\(\Leftrightarrow2013x+\dfrac{2013\left(2013+1\right)}{2}=20132014\)

\(\Leftrightarrow2013x+2027091=20132014\)

\(\Leftrightarrow2013x=18104923\)

\(\Leftrightarrow x=\) (chỗ nãy bẫm mãy tính ra số ngộ quá @@ nên ko ghi vào )