1.

If `x ="log"_(a)(bc), y ="log"_(b)(ca) " and "z = "log"_(c)(ab), ` then which of the following is correct?A. `(1)/(x+1) + (1)/(y+1) + (1)/(z+1) =1`B. `(1)/(x-1) + (1)/(y-1) + (1)/(z-1) =1`C. xyz =x + y + z + 1D. xyz = 1

Answer» Correct Answer - A
We have,
`x = "log"_(a)bc, y = "log"_(b)ca, z = "log"_(c) ab`
`rArr x + 1 = "log"_(a)bc + "log"_(a) a, y+1 = "log"_(b)ca + "log"_(b)b, z+1 = "log"_(c)ab + "log"_(c)c`
`rArr x+ 1 = "log"_(a)abc, y + 1 = "log"_(b)abc, z+1 = "log"_(c)abc`
`rArr (1)/(x+1) + (1)/(y + 1) + (1)/(z+1) = "log"_(abc)a+"log"_(abc)b + "log"_(abc)c`
`rArr (1)/(x + 1) + (1)/(y + 1) + (1)/(z+1) = "log"_(abc) abc = 1`


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