No it's not a function pretty sure
Answer:
A
Step-by-step explanation:
Time Distance
0 0
2 2*25 = 50
4 4*25 = 100
6 6*25= 150
8 8 * 25 = 200
means to say that for any given 
, we can find 
such that anytime 
(i.e. the whenever 
is "close enough" to 5), we can guarantee that 
(i.e. the value of 
is "close enough" to the limit value).
What we want to end up with is
Dividing both sides by 3 gives
which suggests 
is a sufficient threshold.
The proof itself is essentially the reverse of this analysis: Let be given. Then if
and so the limit is 7. QED
120.
To find out how much gas he is using per day, you can use 75/5 which comes to 15. Then multiplying 15 with the 8 days, you get a sum of 120.
Multiply you first equation by 2 to get 4x + 10y = 22
Now the x terms can be eliminated and cancelled out using elimination.
4x + 10y = 22
4x + 3y = 1
To eliminate you need to "subtract", so you need to multiply one of the equations by -1.
4x + 10y = 22
-4x -3y = -1
------------------
0 + 7y = 21
y = 3
Now plug 3 into either one of the equations to get x.
