Theres information missing in the question. There should be one more pair of coordinates
Answer:
(a) yes it does
(b) the rate is constant because the rate of change (slope) is the same throughout the function.
(c) The rate, or rate of change, is -1/2.
y1 - y2/x1-x2
4 - 2/3 - 9
2/-6
-1/2
Answer:
A
Step-by-step explanation:
I drew these, as I just did these in math not too long ago. When I shaded it, it was in all four quadrants.
Let numbers of books be 'b' and numbers of CDs be 'c'
We can set up two equations:
Equation [1] ⇒
![b+c=20](https://tex.z-dn.net/?f=b%2Bc%3D20)
Equation [2] ⇒
![1.50b+5c=54.50](https://tex.z-dn.net/?f=1.50b%2B5c%3D54.50)
We are solving for the number of books and the number of CDs bought
When we have two equations in terms of two different variables;
![b](https://tex.z-dn.net/?f=b)
and
![c](https://tex.z-dn.net/?f=c)
, that we need to solve, then this becomes a simultaneous equation problem.
First, rearrange Equation [1] to make either
![b](https://tex.z-dn.net/?f=b)
or
![c](https://tex.z-dn.net/?f=c)
the subject:
![b+c=20](https://tex.z-dn.net/?f=b%2Bc%3D20)
![b=20-c](https://tex.z-dn.net/?f=b%3D20-c)
Then we substitute
![b=20-c](https://tex.z-dn.net/?f=b%3D20-c)
into Equation [2]
![1.50b+5c=54.50](https://tex.z-dn.net/?f=1.50b%2B5c%3D54.50)
![1.50(20-c)+5c=54.50](https://tex.z-dn.net/?f=1.50%2820-c%29%2B5c%3D54.50)
![30-1.50c+5c=54.50](https://tex.z-dn.net/?f=30-1.50c%2B5c%3D54.50)
![5c-1.5c=54.50-30](https://tex.z-dn.net/?f=5c-1.5c%3D54.50-30)
![3.5c=24.50](https://tex.z-dn.net/?f=3.5c%3D24.50)
![c=7](https://tex.z-dn.net/?f=c%3D7)
Now we know the value of
![c](https://tex.z-dn.net/?f=c)
which is
![c=7](https://tex.z-dn.net/?f=c%3D7)
, substitute this value into
![b=20-c](https://tex.z-dn.net/?f=b%3D20-c)
we have
![b=20-7=13](https://tex.z-dn.net/?f=b%3D20-7%3D13)
Answer:
Numbers of books = 13
Numbers of CDs = 7