Posted by Sara on Wednesday, January 11, 2012 at 7:28pm.
first
x^2+12x+36 = (x+6)(x+6)
so
ln of
(x-7)(x+6)
=====================
(x+6)(x+6)(x+7)(x-7)
ln of
1
=====================
(x+6)(x+1)
= ln 1 - ln(x^2 +7x + 6)
but ln 1 = 0
so
- ln (x^2 + 7 x + 6)