we know that
A relationship between two variables, x, and y, represent a direct variation if it can be expressed in the form
or ![y=kx](https://tex.z-dn.net/?f=y%3Dkx)
in this problem we have
the point
is on the line of direct variation
so
Find the constant of proportionality k
-------> substitute ------> ![k=12/5](https://tex.z-dn.net/?f=k%3D12%2F5)
the equation is
![y=\frac{12}{5}x](https://tex.z-dn.net/?f=y%3D%5Cfrac%7B12%7D%7B5%7Dx)
Remember that
If a point is on the line of direct variation
then
the point must satisfy the equation of direct variation
we're proceeding to verify each point
<u>case A)</u> point ![(0,0)](https://tex.z-dn.net/?f=%280%2C0%29)
![x=0\ y=0](https://tex.z-dn.net/?f=x%3D0%5C%20y%3D0)
Substitute the value of x and y in the direct variation equation
![0=\frac{12}{5}*0](https://tex.z-dn.net/?f=0%3D%5Cfrac%7B12%7D%7B5%7D%2A0)
-------> is true
therefore
the point
is on the line of direct variation
<u>case B)</u> point ![(2.5,6)](https://tex.z-dn.net/?f=%282.5%2C6%29)
![x=2.5\ y=6](https://tex.z-dn.net/?f=x%3D2.5%5C%20y%3D6)
Substitute the value of x and y in the direct variation equation
![6=\frac{12}{5}*2.5](https://tex.z-dn.net/?f=6%3D%5Cfrac%7B12%7D%7B5%7D%2A2.5)
-------> is true
therefore
the point
is on the line of direct variation
<u>case C)</u> point ![(3,10)](https://tex.z-dn.net/?f=%283%2C10%29)
![x=3\ y=10](https://tex.z-dn.net/?f=x%3D3%5C%20y%3D10)
Substitute the value of x and y in the direct variation equation
![10=\frac{12}{5}*3](https://tex.z-dn.net/?f=10%3D%5Cfrac%7B12%7D%7B5%7D%2A3)
-------> is not true
therefore
the point
is not on the line of direct variation
<u>case D)</u> point ![(7.5,18)](https://tex.z-dn.net/?f=%287.5%2C18%29)
![x=7.5\ y=18](https://tex.z-dn.net/?f=x%3D7.5%5C%20y%3D18)
Substitute the value of x and y in the direct variation equation
![18=\frac{12}{5}*7.5](https://tex.z-dn.net/?f=18%3D%5Cfrac%7B12%7D%7B5%7D%2A7.5)
-------> is true
therefore
the point
is on the line of direct variation
<u>case E)</u> point ![(12.5,24)](https://tex.z-dn.net/?f=%2812.5%2C24%29)
![x=12.5\ y=24](https://tex.z-dn.net/?f=x%3D12.5%5C%20y%3D24)
Substitute the value of x and y in the direct variation equation
![24=\frac{12}{5}*12.5](https://tex.z-dn.net/?f=24%3D%5Cfrac%7B12%7D%7B5%7D%2A12.5)
-------> is not true
therefore
the point
is not on the line of direct variation
<u>case F)</u> point ![(15,36)](https://tex.z-dn.net/?f=%2815%2C36%29)
![x=15\ y=36](https://tex.z-dn.net/?f=x%3D15%5C%20y%3D36)
Substitute the value of x and y in the direct variation equation
![36=\frac{12}{5}*15](https://tex.z-dn.net/?f=36%3D%5Cfrac%7B12%7D%7B5%7D%2A15)
-------> is true
therefore
the point
is on the line of direct variation
therefore
<u>the answer is</u>
![(0,0)](https://tex.z-dn.net/?f=%280%2C0%29)
![(2.5,6)](https://tex.z-dn.net/?f=%282.5%2C6%29)
![(7.5,18)](https://tex.z-dn.net/?f=%287.5%2C18%29)
![(15,36)](https://tex.z-dn.net/?f=%2815%2C36%29)