Question

Melissa frosted some cupcakes in the morning for a party. the table shows the total number of cupcakes frosted after she starts up after lunch. assume the relationship between the two quantities is linear. find and interpret the rate of change and the initial value.

Answer 1

Answer:
rate of change = 4/5 = 0.8
initial value = 24

Explanation:
Part (1): getting the rate of change:
The rate of change means the change of the output with respect to the change in the input.
Since we are given that the relation is linear, therefore, the rate of change is constant at any point that belongs.
First, we will need to choose any points from the table. I will choose points : (5,28) and (15,36)
The rate of change is also known as the slope of the line and can be calculated using the following rule:
rate of change = slope of line = (y2-y1) / (x2-x1)
Substitute with the points you chose to get the rate of change as follows:
rate of change = (36-28) / (15-5) = 4/5 = 0.8

Part (2): getting the initial value:
The initial value is defined as the output when the input is zero. Therefore, it is the value of the "y" when the value of the "x" is zero.
The general form of the linear is function is:
y = mx + c
where:
m is the slope
c is the y-intercept
We have the slope = 4/5
Therefore, equation of the line now is:
y = (4/5) x + c
Now, we need to get the y-intercept. To do so, we will use any point that belongs to the function to substitute in the equation and then solve for c. I will choose point (20,40)
y = (4/5) x + c
40 = (4/5)(20) + c
c = 40-16 = 24
Therefore, the equation of the line now becomes:
y = (4/5)x + 24
Now, to get the value, we will substitute the x with zero and get the corresponding y as follows:
y = (4/5)x + 24
y = (4/5)(0) + 24
initial value of y = 24

Hope this helps :)