Question

1

2
3
X
Numedaya
cling magazine
Number of
megnes sold
a
12
15
21
Tom sold magazines for 4 days last week. The table above gives the total number of magazines Tom had
sold for the week at the end of each of the 4 days. Which of the following best models the relationship
between the total number M of magazines Tom sold and the number x of days selling?
O M(x)=x+4
O M(x)= 1.5x +4
20 M(x)= 4x + 4
> M(x)= 6x+4

Answer 1

C.
`M(x) = 4x + 4`

Explanation:

Find the rate of change/slope (m) using two pairs (1, 8) and (2, 12):

`slope (m) = (y_2 - y_1)/(x_2 - x_1) = (12 - 8)/(2 - 1) = (4)/(1) = 4`

(Note: M(x) = y)

Find y-intercept (b) by substituting x = 1, M(x) = 8, and m = 4 in M(x) = mx + b.

Thus:

8 = (4)(1) + b

8 = 4 + b

Subtract 4 from each side

8 - 4 = b

4 = b

b = 4

substitute m = 4, and b = 4 in M(x) = mx + b, to get the equation that models the relationship.

The equation would be:

✅
`M(x) = 4x + 4`