\[\sqrt{98} + \sqrt{242} - \sqrt{50} =\]
\[= \sqrt{49 \cdot 2} + \sqrt{121 \cdot 2} - \sqrt{25 \cdot 2} =\]
\[= 7\sqrt{2} + 11\sqrt{2} - 5\sqrt{2} = 13\sqrt{2}\]