For exercises 1 and 2, translate each phrase into an algebraic expression. 
 1. the difference of a number and sixteen (1 point) 
 A.n + 16 
 B.n – 16 
 C.16n 
 D.n/16 
 2. five times k (1 point) 
 A.5k 
 B.k + 5 
 C.k ÷ 5 
 D.5 – k 
 For exercises 3 and 4, evaluate each expression when s = 9 and t = 12. 
 3. 3(3t + s) (1 point) 
 A.9 
 B.24 
 C.45 
 D.135 
 4. 2s – t (1 point) 
 A.–6 
 B.6 
 C.15 
 D.30