Deduce X from a constant in variance properties

Question

How do you consider $\operatorname{Var}(c-\alpha X)$?

I'm learning that $V(c) = 0$, where $c$ is a constant.

Does it turn the above into:

$0 - \operatorname{Var}(\alpha X) = -[\alpha^2\operatorname{Var}(X)]$

Answer 1

\begin{align} Var(c-aX) &= Var(-aX) \\ &= (-a)^2Var(X) \end{align}

We have $$Var(aX+bY) = a^2Var(X)+b^2Var(Y) + 2abCov(X,Y)$$