The mathematical linear function of PEP is in the eighth grade, and it is in the second volume of the eighth grade, chapter 19. Linear function is a kind of function, and its general form is y=kx+b(k, b is constant, k≠0), where x is independent variable and y is dependent variable. Especially when b=0, y=kx(k is a constant, k≠0), and y is called a direct proportional function of x.

Basic attribute

(1) list: for each value of independent variable x, find a value of dependent variable y and list it.

(2) Plot points: generally, two points are taken, and according to the principle of "two points make a straight line", that is, in the rectangular coordinate system, the point corresponding to the value in the table is plotted with the value of the independent variable as the abscissa and the corresponding function value as the ordinate. Generally, the image of y=kx+b(k≠0) can be drawn after (0, b) and (-b/k, 0).