Not sure if you need it without rounding or anything, but in its exact form, the answer is 3√2 + 3√5.
Explanation: You take √3 and carry it to √6 and √15. This means doing √3 times √6 and √3 times √15. Doing so gives you √18 + √45. Simplifying the roots would give you 3√2 + 3√5. How you get from √18 to 3√2 is that you make a factor tree of 18. Any factor that is the same will be added to the coefficient. In this case, 3 would have to be your coefficient. The factors of 18 are 2, 3, and 3. If there are two of the same factors, you put them together as one. (In this case, the two 3’s would become one 3.) How you get from √45 to 3√5 is doing the exact same process that happened from getting √18 to 3√2 except you would make a factor tree of 45. (The factors of 45 are 5, 3, and 3. Two 3’s make one 3.) Therefore, your answer in exact form would be 3√2 + 3√5. I hope this helps. Sorry if I did not understand the question correctly.
