algebra
posted by Alaska Diamond on .
Radicals are so confusing. Can someone show me step by step please. Im lost
5/8+√7

The main point is to recall that (ab)(a+b) = a^2b^2
So, if you want to get rid of roots in the denominator, multiply top and bottom by the "conjugate" expression
(8+√7)(8√7) = 8^2  √7^2 = 647 = 57
So,
5/(8+√7) = 5(8√7)/((8+√7)(8√7))
= 5(8√7)/57
= (40  5√7)/57