Question

1+2+3+...+x=500500

Answer 1

\(1+2+3+...+x=500500\)

\(\Rightarrow\frac{x\left(x+1\right)}{2}=500500\)

\(x\left(x+1\right)=1001000=1000.1001\)

\(\Rightarrow x=1000\)

Answer 2

1+2+3+...+x=500500

=> (x+1).x : 2 = 500500

=> (x+1).x = 500500 . 2

=>  (x+1).x  = 1001000 

Mà : 1001000 = 1001.1000

=> x = 1000