Răspuns :
numerele cu ultima cifra de 0 poate conduce la patrate perfecte ,
n = 0, n =10
daca n = 10
80 + 1 = 81 si 60 + 4 = 64 sunt patrate perfecte
81 = 9^2
64 = 8^2
10 : 5 = 2 rest 0
n=0,10
n=10
6n+4=6*10+4=64 64=8*8
8n+1=8*10+1=81 81=9*9
n=0
6*n+4=6*0+4=4 4=2*2
8*n+1=8*0+1=1 1=1*1
10:5=2 rest 0
0:5=0 rest 0
n=10
6n+4=6*10+4=64 64=8*8
8n+1=8*10+1=81 81=9*9
n=0
6*n+4=6*0+4=4 4=2*2
8*n+1=8*0+1=1 1=1*1
10:5=2 rest 0
0:5=0 rest 0