Simplifying Radicals help please again, lol?

[lance]

The problem is the square root of 3 times the square root of 12. Please show work and explain, Thank You!

 

[caro]

just multiply 3 times 12 and your answer is the square root of 36 which is 6

 

[Andrew1]

Because both terms are under radicals and are being multiplied, they can be joined into 1 radical.
sqrt3*sqrt12=sqrt(3*12)=sqrt36=6
If the two were being added, then you could not combine the radicals.