Question: I am visualizing what scaling a vector does to its original vector, it can expand it, shrink it, flip it the other way, but is there such thing as a scalar changing the only the $y$ value of a vector?

For instance you have the vector $(2,3)$ does there exist such scalar that would produce $(2,-3)$?

I am just curious. I think there isn't one, but just wanted to check with you guys.

Answer: 
Here is how to "see" the only solution:

* $\lg 2 = \frac{\log\_2 2}{\log\_2 10} = \frac{1}{\log\_2 10}$
* $x^{\lg 2} = 2^{\log\_2 x}$

So, the equation becomes
$$x-8 = x^{\lg(2)} \Leftrightarrow x - 2^{\frac{\log\_2 x}{\log\_2 10}} = 8$$

This equation has obviously the solution $x=10$.

The uniqueness follows (as already mentioned in other solution) from considering the monotonicity of $x - 2^{\frac{\log\_2 x}{\log\_2 10}}$.
$x=10$ is the solution since
$$
10^{\lg 2}=2=10-8
$$
To prove that there are no other solutions just plot left and right functions