Now, if `y=c\ ln\ x`, then `(dy)/(dx)=c/x`


[See Derivative of the Logarithmic Function if you are rusty on this.)

So

`"LHS"=(dy)/(dx)ln\ x-y/x`

`=(c/x)\ ln\ x-((c\ ln\ x))/x`

`=0`

`="RHS"`

We conclude that we have the correct solution.

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