Answer:
Step-by-step explanation:
This is a special right triangle that has 30, 60 and 90 degress corners. Because it is a special triangle, it also has side length values which always consistent relationship with one another.
Side opposite the 30° angle: x
Side opposite the 90° angle: 2x
So, 
Then use Pythagorean theorem. 




Your answer would be y + 9 = m(x + 6)
What measurement unit do you want it in? and on a graph?