Find the indicated values for the given function: $$f(x) = \begin{cases} 2 x - 4, &\text{if}\ x\leq 1\\ -2 x + 5, &\text{if}\ x>1 \end{cases}$$ a) $f(4)$ =

b) $f(-3)$ =

c) $f(1)$ =