Use the Given Information to Compute $\tan ( s + t )$

Multiple Choice

Use the given information to compute $\tan ( s + t )$ and $\tan ( s - t )$ . $\tan s = 5$ and $\tan t = 4$

A) $\tan ( s + t ) = - \frac { 9 } { 19 }$ $\tan ( s - t ) = \frac { 1 } { 21 }$
B) $\tan ( s + t ) = - \frac { 1 } { 21 }$ $\tan ( s - t ) = \frac { 9 } { 19 }$
C) $\tan ( s + t ) = - \frac { 19 } { 9 }$ $\tan ( s - t ) = \frac { 21 } { 1 }$
D) $\tan ( s + t ) = \frac { 5 } { 6 }$ $\tan ( s - t ) = - \frac { 5 } { 6 }$
E) $\tan ( s + t ) = - \frac { 21 } { 1 }$ $\tan ( s - t ) = \frac { 19 } { 9 }$