Answer:
The first term is:
Step-by-step explanation:
The arithmetic sequence is defined by

where
is the first term
is the common difference
as
the 17th term of an arithmetic sequence is 51.
i.e. 
so

∵
,
, 
∵ 

Therefore, the first term is:
Answer: Andrew = 90 pounds
Explanation:
Assume Andrew weight is X
Since Jackson weight is 3 times Andrew
Then it’s 3x
3x + x = 360
4x = 360
x = 90
Answer:
x=9
y=16
z=12
Step-by-step explanation: