Answer:
2(z+3)
Step-by-step explanation:
z+ (z+6)
combine like terms
=2z+6
factor out a 2
=2(z+3)
(z+z) + (z+6) = 3z+6 so no
(z+6) +6 = z+12 so no
16
the numbers are divided by 4 to form a sequence so 64 divided by 4 is 16