n-o sa le fac pe toate, posteaza-le separat!
1.a. n∈N
n³/4=(n²/2):2
n³/4=n²/4
n³=n²
n=0 sau 1
S={0; 1}
b. abcd nr in baza 10, a, b, c, d cifre a≠0
4abcd=3·abcd3
4abcd=40000+1000a+100b+10c+d
abcd3=10000a+1000b+100c+10d+3
40000+1000a+100b+10c+d=30000a+3000b+300c+30d+9
29000a+2900b+290c+29d=39991
29(1000a+100b+10c+d)=39991
1000a+100b+10c+d=1379
abcd=1379
