the equation -15x+4y=0 relates the length of a videotape in inches x to its approximate playing time in seconds y. will give medal!!!

Question

anonymous · Answer

What is your question?  You've given a bunch of information but haven't actually asked anything.

anonymous · Answer

tell whether each relationship is a direct variation and why

anonymous · Answer

An equation represents direct variation if it is of the form:

$$y=kx$$ (Which is a special case of y=mx+b  with b=0)

To find out if our equation is direct variation we need to solve for y:
$$-15x+4y=0$$$$4y=15x$$$$y=\frac{ 15 }{ 4 }x$$
We can see that his matches the pattern of 
$$y=kx$$ with k=15/4


So, yes, this equation is direct variation. 

The reason is because the ration between x and y is always the same (in this case 15/4). If we double x we double y. If we triple x we triple y. etc. etc.