N
nhokmoon_18


log7\(x^2+x+1)>= log2\x
hic ko bit go~ cong thuc", aj go~ lai dum` mih voi, rui ` nho` giai luon ^^ ,thk
2 va` 7 la` chi? so' duoi' do'
hic ko bit go~ cong thuc", aj go~ lai dum` mih voi, rui ` nho` giai luon ^^ ,thk
2 va` 7 la` chi? so' duoi' do'