If $\displaystyle f(x) = \begin{cases} -5 x + 6 & \text{for } x \le 0 \\ 9 x - 4 & \text{for } x > 0 \end{cases}$, find the following values.

1. $f(-4) =$

2. $f(0) =$

3. $f(2) =$

4. $f(3) =$

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