Ответ:\((\sqrt5-\sqrt7)^2=5-2\sqrt{35}+7=12-2\sqrt{35}\).\((\sqrt6-1)(\sqrt6+1)=(\sqrt6)^2-1^2=6-1=5\).\((4-\sqrt7)^2=16-8\sqrt7+7=23-8\sqrt7\).\((\sqrt6-3)(\sqrt6+3)=(\sqrt6)^2-3^2=6-9=-3\).