Let me rephrase the question in another way: "

*Is * **always **true? -- Answer: Yes/No" And the answer was "No.", as you guys explained that it would depend on whether r is a postive or a negative.

That's the part I was confused about.

So I guess in cases where we don't know any information about the variable r (where it's positive or negative), cross multiplying to make a easier visual representation (where I made the equation

) of the problem would be ill advised. That's what I'm getting here. Is that about right?