1+2+3+4+...+x=500500
\(\frac{\left(x+1\right).x}{2}=500500\)
\(\left(x+1\right).x=1001000\)
\(1001.1000=100100\)
Vậy x = 1000
1+2+3+4+...+X = 500500
( X + 1 ) x X : 2 = 500500
( X + 1) x X = 500500 x 2
( X + 1) x X = 1001000
1000 x ( 1000+ 1) = 1001000
Vậy x = 1000
Theo công thức ta có:
\(\frac{x\left(x+1\right)}{2}=500500\Leftrightarrow x^2+x-1001000=0\Leftrightarrow x=1000\)
\(1+2+3+4+...+x=500500\)
\(\left(1+x\right).x\div2=500500\)
\(\left(1+x\right).x=500500.2\)
\(\left(1+x\right).x=1001000\)
\(\left(1+x\right).x=1001.1000\)
\(\Rightarrow x=1000\)
1 + 2 + 3 + 4 + ... + x = 500500
(x + 1) . x : 2 = 500500
(x + 1) . x = 500500 x 2
=(x + 1) . x = 1001000
= 1001 x 1000
= > x là 1000
