Tap the blue circles to see an explanation.
$$ \begin{aligned}-8\sqrt{63}+\sqrt{112}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-24\sqrt{7}+4\sqrt{7} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}-20\sqrt{7}\end{aligned} $$ | |
① | $$ - 8 \sqrt{63} =
-8 \sqrt{ 3 ^2 \cdot 7 } =
-8 \sqrt{ 3 ^2 } \, \sqrt{ 7 } =
-8 \cdot 3 \sqrt{ 7 } =
-24 \sqrt{ 7 } $$ |
② | $$ \sqrt{112} =
\sqrt{ 4 ^2 \cdot 7 } =
\sqrt{ 4 ^2 } \, \sqrt{ 7 } =
4 \sqrt{ 7 }$$ |
③ | Combine like terms |