Answer:
- [tex]\sqrt[3]{81}=3\sqrt[3]{3}[/tex]
- [tex]\sqrt[3]{-64}=-4[/tex]
Step-by-step explanation:
a)
[tex]\sqrt[3]{81}=\sqrt[3]{3^4}=\sqrt[3]{(3^3)(3)}=3\sqrt[3]{3}[/tex]
This is irrational.
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b)
[tex]\sqrt[3]{-64}=\sqrt[3]{(-4)^3}=-4[/tex]
This is rational.
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Please be aware that 3 square root of 81 is not the same as cube root of 81.
[tex]3\sqrt{81}\ne\sqrt[3]{81}[/tex]
You can call a cube root what it is.
