Let's draw it, function y=3x
To draw it we need two points, like this:
[tex]\begin{gathered} y=3x \\ \text{if x = 0, then } \\ y=3\cdot0=0 \\ (0,0)\text{ is the first point}\ldots \\ \text{now, if x=1, then} \\ y=3\cdot1=3 \\ (1,3)\text{ is the second point}\ldots \end{gathered}[/tex]
We draw point (0,0) with colour red and point (1,3) with colour green. After that we gonna draw y=3x with colour blue
