Răspuns :
[tex]12^2+16^2 =\\ \\ =(4\cdot 3)^2+(4\cdot 4)^2\\ \\ = 4^2\cdot 3^2+4^2\cdot 4^2\\ \\ = 4^2\cdot (3^2+4^2)\\ \\ =4^2\cdot (9+16)\\ \\ =4^2\cdot 25 \\ \\ = 4^2\cdot 5^2\\ \\ = (4\cdot 5)^2\\ \\ =\boxed{20^2}[/tex]
[tex]12^2+16^2 =\\ \\ =(4\cdot 3)^2+(4\cdot 4)^2\\ \\ = 4^2\cdot 3^2+4^2\cdot 4^2\\ \\ = 4^2\cdot (3^2+4^2)\\ \\ =4^2\cdot (9+16)\\ \\ =4^2\cdot 25 \\ \\ = 4^2\cdot 5^2\\ \\ = (4\cdot 5)^2\\ \\ =\boxed{20^2}[/tex]