Question

demonstrează ca nr a este pastrat perfect unde a=1+2+3+...+100+51×101

Answer 1

1+2+3+...+100 = 100*101/2 = 50*101
50*101+51*101 = 
101 (50+51) = 
101*101 => numarul e patrat perfect

Answer 2

1+2+...+100+51×101=
=100×101:2+51×101
=50×101+51x101
=101 (50+51)
=101×101
=101^2
q.e.d.