Answer:
[tex]\begin{array}{ll}\bullet&6\sqrt{qr^3}\\\bullet&6r\sqrt{qr}\end{array}[/tex]
Step-by-step explanation:
The product of the square roots is equal to the square root of the product.
[tex]\sqrt{12qr^2}\cdot\sqrt{3r}=\sqrt{12\cdot 3qr^3}=\sqrt{6^2qr^3}=6\sqrt{qr^3}\\\\=6r\sqrt{qr}[/tex]
The factor of r^2 can be left under the radical or not, since all you want is an equivalent expression. If you want the expression completely simplified, then you need to write it as ...
[tex]6r\sqrt{qr}[/tex]
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IMO, the question posed has two right answers: the second and fourth choices. Your grader may want to see only the fourth choice.
