Graph the line.
$$y=4x$$

Step 1 ：The given equation is $y=4x$. This is a linear equation in two variables x and y.

Step 2 ：The slope of the line is 4. The slope of a line is the ratio of the vertical change (the change in y) to the horizontal change (the change in x).

Step 3 ：The line passes through the origin (0,0) because when x=0, y=0.

Step 4 ：To graph the line, we plot the line on a 2D graph with x and y ranging from -10 to 10.

Step 5 ：The graph of the line is a straight line that passes through the origin and has a slope of 4. The line increases as x increases and decreases as x decreases.

Step 6 ：$\boxed{{\displaystyle \text{The graph of the line }y=4x\text{ is a straight line that passes through the origin and has a slope of 4.}}}$