The unit price of a notebook is 5 yuan. It takes y yuan to buy x (x ∈ {1,2,3,4,5} laptops. Try three expressions of the function y = f (x)

The unit price of a notebook is 5 yuan. It takes y yuan to buy x (x ∈ {1,2,3,4,5} laptops. Try three expressions of the function y = f (x)

List method 1 2 3 4 5
5 10 15 20 25 yuan
Function method
Y=5(X=1)
Y=10(X=2)
Y=15(X=3)
Y=20(X=4)
Y=25(X=5)
Image method
Draw a coordinate, abscissa is the number, ordinate is the yuan, point is the description