Joe's Painting: 20x + 100 = y
Steve's Painting: 15x + 120 = y
x = hours worked
y = total income
We can find when the two equations intersect by making them equal to each other. That means we put an equal sign in the middle. So, it would look something like this:
20x + 100 = 15x + 120
First, we have to move the 100 by subtracting it from both sides.
20x = 15x + 120 - (100)
20x = 15x + 20
Then, we need to move the 15x by subtracting it from both sides.
20 - (15x) = 20
5x = 20
Lastly, we need to divide 5 from both sides.
5x = 20/5
x = 4
Therefore, Joe and Steve would have to work for 4 hours in order for their models to be equal to each other.
Answer: It is tripled.
Since x and y are proportional, whatever happens to x must happen to y in order for the two values to stay proportional.
Part A:
The average rate of change refers to a function's slope. Thus, we are going to need to use the slope formula, which is:

and
are points on the function
You can see that we are given the x-values for our interval, but we are not given the y-values, which means that we will need to find them ourselves. Remember that the y-values of functions refers to the outputs of the function, so to find the y-values simply use your given x-value in the function and observe the result:




Now, let's find the slopes for each of the sections of the function:
<u>Section A</u>

<u>Section B</u>

Part B:
In this case, we can find how many times greater the rate of change in Section B is by dividing the slopes together.

It is 25 times greater. This is because
is an exponential growth function, which grows faster and faster as the x-values get higher and higher. This is unlike a linear function which grows or declines at a constant rate.