Tap the blue circles to see an explanation.
$$ \begin{aligned}3\sqrt{5}+5\sqrt{20}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}3\sqrt{5}+10\sqrt{5} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}13\sqrt{5}\end{aligned} $$ | |
① | $$ 5 \sqrt{20} =
5 \sqrt{ 2 ^2 \cdot 5 } =
5 \sqrt{ 2 ^2 } \, \sqrt{ 5 } =
5 \cdot 2 \sqrt{ 5 } =
10 \sqrt{ 5 } $$ |
② | Combine like terms |