Find the Slope of the Curve at the Indicated Point $f ( x ) = \frac { 1 } { x + 1 }$

Multiple Choice

Find the slope of the curve at the indicated point.
-Find equations of all tangents to the curve $f ( x ) = \frac { 1 } { x + 1 }$ that have slope $- 1$ .

A) $y = - x + 3$
B) $y = - x + 1 , y = - x - 3$
C) $y = - x + 3 , y = - x + 1$
D) $y = - x + 1$