Find a Formula for the Slope of the Graph Of f

Multiple Choice

Find a formula for the slope of the graph of $f ( x ) = \frac { 7 } { x + 4 }$ .

A) $\frac { 7 } { ( x + 4 ) ^ { 2 } }$
B) $\frac { 7 } { x + 4 }$
C) $- \frac { 1 } { 7 ( x + 4 ) ^ { 2 } }$
D) $- \frac { 7 } { ( x + 4 ) ^ { 2 } }$
E) $- \frac { 7 } { x + 4 }$