Question

Calculati √ab + ba, stiind ca cifrele a si b verifica egalitatea a+b = 11

Answer 1

$a+b=11$
ab si ba scris in baza 10
$\sqrt{ab+ba} = \sqrt{10a+b+10b+a} = \sqrt{11a+11b} = \sqrt{11*(a+b)}=$$\sqrt{11*11} = \sqrt{121} =11$