Question

x=2( 1+ 2+ 3+... + 98)+99

Answer 1

Gauss zice asa:

1+2+3+...+n=n(n+1)/2

noi o sa avem
98*99/2

2* 98*99/2 + 99 = simplificam 2 cu 2=
98*99+99=
99(98+1)=
99*99 => nr e patrat perfect = 9801

Answer 2

 $x=\not2_1\cdot\frac{98\cdot99}{\not2_1}\,+\,99=99\cdot(98+1)=99^2=9801$