In order to make a table, we sample some x values (whichever we want), and we compute the expression for those value. Each x value will yield a unique y value.
If you need this table to graph the function, you'll only need two points, since this is a line, and having two points you just need to connect them.
Here are some samples, feel free to make more if you need to:
[tex]f(x)=2x+4\implies f(0)=2\cdot 0 + 4 = 4[/tex]
[tex]f(x)=2x+4\implies f(1)=2\cdot 1 + 4 = 6[/tex]
[tex]f(x)=2x+4\implies f(2)=2\cdot 2 + 4 = 8[/tex]
[tex]f(x)=2x+4\implies f(3)=2\cdot 3 + 4 = 10[/tex]
[tex]f(x)=2x+4\implies f(4)=2\cdot 4 + 4 = 12[/tex]
So, we have the following table
[tex]\begin{array}{c|c}0&4\\1&6\\2&8\\3&10\\4&12\end{array}[/tex]
