2004 #18 and 24

Surprisingly easy for this late in the test.

Difficulty: easy.

Difficulty: Changing everything to a common base goes a long way here.

Standard instructions for this series: No calculator allowed. Express answers in reduced form. Rationalize denominators. Radicals must be reduced. All numbers are base ten unless otherwise specified. Do not approximate radicals or π. Leave such answers as 1025π or √39, for example. Source: UVM Math Contest 2004

answer 18, answer 24.