<PRE><B>Question 66452</B>
 im having trouble with 2 radical 7 over 3 radical 5 + 5 radical 3. I know to multiply the top and bottom by 3 radical 5 + 5 radical 3 but what im getting doesnt seem right.
0 solutions


You are on the right track except that you multiply the top and bottom by      3 radical 5 - 5 radical 3.  This is called the conjugate and in this case it will get rid of the radicals in the denominator.


2sqrt7/(3sqrt5+5sqrt3)  multiply top and bottom by (3sqrt5-5sqrt3) and we get:

(2sqrt7(3sqrt5-5sqrt3))/((3sqrt5+5sqrt3)(3sqrt5-5sqrt3))  multiplying we get:

(6sqrt(7)(5)-10sqrt(7)(3))/(45-75) and this equals
6sqrt(7)(5)-10sqrt(7)(3))/(-30) dividing top and bottom by 2
(3sqrt(7)(5)-5sqrt(7)(3))/-15  factor out sqrt7 in the numerator:

(sqrt7(3sqrt5-5sqrt3))/-15


This should be it---ck using a calculator


Hope this helps----ptaylor</PRE>