Tap the blue circles to see an explanation.
| $$ \begin{aligned}\sqrt{28}+4\sqrt{63}-2\sqrt{7}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}2\sqrt{7}+12\sqrt{7}-2\sqrt{7} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}12\sqrt{7}\end{aligned} $$ | |
| ① | $$ \sqrt{28} =
\sqrt{ 2 ^2 \cdot 7 } =
\sqrt{ 2 ^2 } \, \sqrt{ 7 } =
2 \sqrt{ 7 }$$ |
| ② | $$ 4 \sqrt{63} =
4 \sqrt{ 3 ^2 \cdot 7 } =
4 \sqrt{ 3 ^2 } \, \sqrt{ 7 } =
4 \cdot 3 \sqrt{ 7 } =
12 \sqrt{ 7 } $$ |
| ③ | Combine like terms |