This is the problem that I am having trouble with for my test review. I am completely blank and don't know what it is asking for. Can you please guide me step by step. For example: Why did constant $k$ appear all of a sudden?
$a$ varies directly with $b$
Which of these equations could represent the relationship between $a$ and $b$?
$a$ varies directly with $b$ if $a=k\cdot b$ for some constant $k$
If you divide each side of this expression by $b$, you get $\displaystyle\frac ab=k$ for some constant $k$.
$\displaystyle\frac ab=\frac12$ fits this pattern, with $k=\displaystyle\frac12$
- $\frac12\cdot a=\frac1b$
- $\frac ab=\frac12$