Question
Answer
$$\dfrac{-4}{\sqrt{8}}=-\sqrt{2}$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}\frac{-4}{\sqrt{8}}& \xlongequal{ }-\frac{4}{\sqrt{8}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}- \, \frac{ 4 }{\sqrt{ 8 }} \times \frac{ \color{orangered}{\sqrt{ 8 }} }{ \color{orangered}{\sqrt{ 8 }}} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-\frac{4\sqrt{8}}{8} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}- \, \frac{ 4 \sqrt{ 4 \cdot 2 }}{ 8 } \xlongequal{ } \\[1 em] & \xlongequal{ }- \, \frac{ 4 \cdot 2 \sqrt{ 2 } }{ 8 } \xlongequal{ } \\[1 em] & \xlongequal{ }-\frac{8\sqrt{2}}{8} \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}}- \, \frac{ 8 \sqrt{ 2 } : \color{blue}{ 8 } }{ 8 : \color{blue}{ 8 } } \xlongequal{ } \\[1 em] & \xlongequal{ }-\frac{\sqrt{2}}{1} \xlongequal{ } \\[1 em] & \xlongequal{ }-\sqrt{2}\end{aligned} $$ | |
| ① | Multiply both top and bottom by $ \color{orangered}{ \sqrt{ 8 }}$. |
| ② | In denominator we have $ \sqrt{ 8 } \cdot \sqrt{ 8 } = 8 $. |
| ③ | Simplify $ \sqrt{ 8 } $. |
| ④ | Divide both the top and bottom numbers by $ \color{blue}{ 8 }$. |
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