First you would subtract 30 from both sides
they divide each side by 5 to get -7
y =-7
Answer: Option C

Step-by-step explanation:
Whenever we have a main function f(x) and we want to transform the graph of f(x) by moving it vertically then we apply the transformation:

If
then the graph of k(x) will be the graph of f(x) displaced vertically b units down.
If
then the graph of k(x) will be the graph of f(x) displaced vertically b units upwards.
In this case we have

We know that this function has its vertex in point (0,0).
Then, to move its vertex 7 units down we apply the transformation:
.
Then the function k(x) that will have its vertex 7 units below f(x) is

It is B because I had the question before in my school
The formula for tan is opposite/adjacent.
This being said, 12/13 would equal approximately 0.923077.
Hope this helps. ^^