Answer:
Function:
c = f(w) = 0.49, 0 < w ≤ 1
= 0.70, 1 < w ≤ 2
= 0.91, 2 < w ≤ 3
Step-by-step explanation:
Yes, the relation described can be interpreted as a function.
Here, c is the cost of a mail letter. c depends upon w, which is the weights of the mail letter.
As described in the question, the relation can be expressed as a function.
c can be expressed as a function of w in the following manner:
c(cost of mail) = f(w), where w is the independent variable and c is the dependent variable
c = f(w) = 0.49, 0 < w ≤ 1
= 0.70, 1 < w ≤ 2
= 0.91, 2 < w ≤ 3
where, c is in dollars and w is in ounces.
The general equation of a line is:

When m is the gradient and x1 and y1 are the coordinates of the points on the line
Therefore:


Yes you take 3 times 4 and receive 12 and 5 times 4 and receive 20
The answer for number 3 is 96.7 if you want the work shown I would recommend you to download the app Socratic and for number six you multiply.75x14 then also multiply.35x7 then add add up the answers which will be 12.95 then you subtract that from 15 the answer is $2.05