Answer: A) 35
Step-by-step explanation:
We have the following:
[tex]\sqrt{215 x}[/tex]
Now, [tex]215[/tex] is made up of two factors, [tex]43[/tex] and [tex]5[/tex]:
[tex]215=(43)(5)[/tex]
So, we have to choose a number for x containing a factor of [tex]43[/tex] and or [tex]5[/tex]. In this case, the best option is [tex]35=(7)(5)[/tex]:
Hence:
[tex]\sqrt{215 (35)}=\sqrt{(43)(5)(7)(5)}[/tex]
[tex]\sqrt{215 (35)}=\sqrt{(25)(43)(7)}=\sqrt{25} \sqrt{301}[/tex]
Finally:
[tex]\sqrt{215 (35)}=5 \sqrt{301}[/tex]