Tap the blue circles to see an explanation.
| $$ \begin{aligned}10\sqrt{5}+\sqrt{80}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}10\sqrt{5}+4\sqrt{5} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}14\sqrt{5}\end{aligned} $$ | |
| ① | $$ \sqrt{80} =
\sqrt{ 4 ^2 \cdot 5 } =
\sqrt{ 4 ^2 } \, \sqrt{ 5 } =
4 \sqrt{ 5 }$$ |
| ② | Combine like terms |