Răspuns :
x=1004+ 2(1+2+...+1003)
x=1004+ 2• (1003•1004):2
x=1004+ 1003•1004
x=1004+ 1.007.012 => x-pătrat perfect
x=1004+ 2• (1003•1004):2
x=1004+ 1003•1004
x=1004+ 1.007.012 => x-pătrat perfect