Question 49918
I am going to use the notation "rt" for "square root of", so the problem is (2rt3-3rt10)(6rt10-3rt3).  Now, we use the FOIL method, or any method of multiplying binomials.  If it is confusing for you to use radicals, you can pretend the rt3 and rt10 are variables, like x and y.  So you get 12rt3rt10 - 6rt3rt3 - 18rt10rt10 + 9rt10rt3.  rt3rt10 = rt10rt3 = rt30, rt3rt3=3, and rt10rt10=10, so we get 12rt30-18-180+9rt30, so the final answer is 21rt30-198.