Question

How do you graph `y=2x`?

Answer 1

Your graph would look like this:
graph{2x [-2.1, 2.1, -5, 5]}

Explanation:

First, you need a starting point. `x=0` is a good solution because, when `x=0`, then `y=2*x=2*0=0`. Thus, your starting point will be `(0;0)`.

Now, the equation `y=2x` means that `y` has an increasing -or decreasing- rate twice as big as `x`'s.
Therefore, every time `x` will be increased -or decreased- by a certain amount, `y` will be increased -or decreased- by the double amount.

A few points that this function's curve will pass through:

`(0;0)`
`(1;2)`
`(2;4)`
`(-1;-2)`