Answer:
[tex]\sqrt[20]{v^{21}}[/tex]
Step-by-step explanation:
[tex]\sqrt[4]{v} \sqrt[5]{v^4}[/tex]
Rearrange both os these radicals into v with a fraction exponent
[tex]v^{\frac{1}{4}}v^{\frac{4}{5} }[/tex]
Make them both have the same denominator
[tex]v^{\frac{5}{20}}v^{\frac{16}{20}}[/tex]
To multiply numbers with exponents with same base you just add the exponents
[tex]v^\frac{21}{20}[/tex]
Now revert it back into a radical
[tex]\sqrt[20]{v^{21}}[/tex]
I hope this helps
