Answer:
The answer is c, C=1.5w + 5
Explanation:
Let's write a general equation first,
C = mw + b, where C represents the shipping cost, w is the weight, m and b are non-zero constants.
By using the set of data in the table, what we can do is to substitute the corresponding values into our general equation. [Use any 2 set of numbers]
11 = 4w + b --(1)
17 = 8w + b --(2)
Here we got 2 equations, 2 unknown, thus we can get
w = 3/2, b = 5
The answer is c, C=1.5w + 5
[Noted that if you already got the slope(the yellow words), you can simply substitute one set of numbers into C=1.5w + b to find the value of b]