1+2+3+4+5+...+x=\(\overline{aaa}\)
=>\(\frac{x\left(x+1\right)}{2}=100\cdot a+10\cdot a+a=111a\)
=>\(x\left(x+1\right)=222a=6\cdot37a=6a\cdot37\)
=>6a=36
=>a=6
=>x(x+1)=36*37
=>x=36
Đúng 0
Bình luận (0)