Answer:
8
Explanation:
Step-1 : Multiply the coefficient of the first term by the constant 1 • -16 = -16 
Step-2 : Find two factors of -16 whose sum equals the coefficient of the middle term, which is 6 .
 -16 + 1 = -15 
 -8 + 2 = -6 
 -4 + 4 = 0 
 -2 + 8 = 6 That's it
Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -2 and 8 
 p2 - 2p + 8p - 16
Step-4 : Add up the first 2 terms, pulling out like factors :
 p • (p-2)
 Add up the last 2 terms, pulling out common factors :
 8 • (p-2)
Step-5 : Add up the four terms of step 4 :
 (p+8) • (p-2)
 Which is the desired factorization