long math

ln( 7 ) + ln (n - 2) = ln( 6n)
with: ln( x*y ) = ln(x)+ln(y)

ln ( 7 * (n-2) ) = ln( 6n )
e^x on both sides (if n>0)

7 * (n-2) = 6n
7n - 14 = 6n
7n - 6n = 14
n = 14