The product $(3-\sqrt{5})(4+\sqrt{5})(1+6\sqrt{5})$ can be expressed in the form $a+b\sqrt{5}$, where $a$ and $b$ are integers. Find $a+b$.
\((3-\sqrt{5})(4+\sqrt{5})(1+6\sqrt{5}) \)
First two products = 7 -sqrt 5
So (7 -sqrt 5) (1 + 6sqrt 5) =
7 -sqrt 5 + 42sqrt 5 - 6*5 =
-23 + 41sqrt 5
a + b = 18
+513 
