Question

How do I plot this;
F(x)={3-x, x is less than or equal to 1
{2x, x is greater than 1

Answer 1

\[f(x)=\begin{cases}3-x&\text{if $x\le1$}\\
2x&\text{if $x>1$}\end{cases}\]

The filled dot means 1 is included (which comes from ≤) and the empty dot means 1 is not included. Does that make sense?