In junior high school mathematics, we usually learn some basic function images, such as linear function, quadratic function, absolute value function and so on. Let's take a linear function as an example to introduce how to draw its image:

The general formula of a linear function is y = kx+b, where k and b are constants respectively, indicating the slope and intercept of a straight line. We can draw an image of this function according to this formula.

1. First determine the coordinate system: in the plane rectangular coordinate system, the abscissa is the X axis and the ordinate is the Y axis.

2. Determine two points: Because the linear function is a straight line, you only need to determine two points to draw the whole straight line. You can choose any two points to determine a straight line.

3. Calculate the slope: calculate the slope k through two known points. The formula is k = (y2-y 1)/(x2-x 1).

4. Intercept calculation: Calculate the intercept b through the known point and slope k .. The formula is b = y-kx.

5. Draw an image: Draw a straight line on the coordinate system according to the calculated slope and intercept.

For example, to draw an image with y = 2x+ 1:

1. Determine the coordinate system.

2. Select two points: (0, 1) and (1, 3).

3. Calculation slope: k = (3- 1)/( 1-0) = 2.

4. Calculate intercept: b = 1-2*0 = 1.

5. Draw a straight line y = 2x+ 1 on the coordinate system.

I hope this simple step can help you draw the image of the function at once.