Option A:  
 is the expression that correctly uses the formula
 is the expression that correctly uses the formula 

Step-by-step explanation:
It is given that, the number line segment from Q to S has endpoints Q at –14 and S at 2.
Point R partitions the directed line segment from Q to S in a 3:5 ratio.
Thus, we have,
 ,
 , 
 ,
 , 
 and
 and 

The location of point R can be determined using the formula,

Substituting the values, we get,

Hence, substituting the values 
 ,
 , 
 ,
 , 
 and
 and 
 in the formula
 in the formula 
 , we get,
, we get, 

Thus, the expression that correctly uses the formula is 

Therefore, Option A is the correct answer.