How Do You Graph The Linear Equation Y=3x?

You plot this linear equation the way you plot any linear equation. Find a couple of points that satisfy the equation and draw a line through them.

By inspection, there is no non-zero y-intercept, so (x, y) = (0, 0) is one point.
When x=1, y=3, so (x, y) = (1, 3) is another point.

Plot these and draw a line through them extending to the edges of your plot in both directions.

Label and mark the divisions on the axes, put a title on the graph (for example, "Graph of y = 3x" along with the problem number), put your name, date, assignment identifier, and class on the paper, and you are finished.