[tex]\sqrt{7}[/tex]
Explanation
[tex]\frac{\sqrt{21}}{\sqrt{3}}[/tex]
Step 1
replace the value of 21 by 3*7
3*7=21
[tex]\begin{gathered} \frac{\sqrt{21}}{\sqrt{3}} \\ \\ \frac{\sqrt{7\cdot3}}{\sqrt{3}} \end{gathered}[/tex]
Step 2
root of 3 is eliminated
[tex]\begin{gathered} \frac{\sqrt{7\cdot3}}{\sqrt{3}} \\ \\ \frac{\sqrt{7}\sqrt{3}}{\sqrt{3}} \\ \frac{\sqrt{7}}{1} \end{gathered}[/tex]
so, the answer is
[tex]\sqrt{7}[/tex]
