Find the sum of all solutions to
(log2x)(log3x)(log4x)(log5x)=(log2x)(log3x)(log4x)+(log2x)(log3x)(log5x)+(log2x)(log4x)(log5x)+(log3x)(log4x)(log5x).
The answer is 1 + 2 + 3 + 4 = 10.