operations with radical expressions

[Desan65]

How do solve the following problem? square root of 15 minus square root of 3/5.

I did square root of 3/5 multiplied by square root of 5/5 = square root of 15 over 5. My answer is square root of 15 minus square root of 15 over 5. Doesn't seem correct!?

 

[Desan65]

= sqrt(3)sqrt(5) - sqrt(3)/sqrt(5)

= 4sqrt(3) / sqrt(5)

I still don't see how you got your answer. Can you explain how you got those numbers? Thanks!

 

[pka]

I still don't see how you got your answer. Can you explain how you got those numbers? Thanks!

\(\displaystyle \sqrt3\,\sqrt5 - \frac{\sqrt3}{\sqrt5}=\frac{5\sqrt3 -\sqrt3}{\sqrt5}=\frac{4\sqrt3 }{\sqrt5}\)