Answer
$17\sqrt{2}-15\sqrt{3}$
Work Step by Step
Using the properties of radicals, then,
\begin{array}{l}
2\sqrt{50}-3\sqrt{125}+\sqrt{98}
\\=
2\sqrt{25\cdot2}-3\sqrt{25\cdot3}+\sqrt{49\cdot2}
\\=
2\cdot5\sqrt{2}-3\cdot5\sqrt{3}+7\sqrt{2}
\\=
10\sqrt{2}-15\sqrt{3}+7\sqrt{2}
\\=
(10\sqrt{2}+7\sqrt{2})-15\sqrt{3}
\\=
17\sqrt{2}-15\sqrt{3}
.\end{array}
