Solve 2√5+7√73√5

We have $2\sqrt{5}$, $7\sqrt{7}$, and $3\sqrt{5}$.

The terms with $\sqrt{5}$ can be combined.
$2\sqrt{5} - 3\sqrt{5} = (2-3)\sqrt{5} = -1\sqrt{5} = -\sqrt{5}$

$-\sqrt{5} + 7\sqrt{7}$

The expression cannot be simplified further as $\sqrt{5}$ and $\sqrt{7}$ are not like terms.