(1) if car a starts from a certain place at a speed of 60km / h, write down the distance S1 (km) and its speed A and B trucks are driving on a highway at a constant speed. (1) If car a starts from a certain place at a speed of 60km / h, write the functional relationship between its driving distance S1 (km) and its driving distance t (H), and draw his image. (2) if car B starts from the same place 2 hours after car a starts and drives along the same direction at a speed of 80km / h, its driving distance S2 (km) is also a function of the driving time t (H) after car a starts, write its driving distance S2 (km) (3) find out the coordinates of the intersection of two images, and explain the practical significance of the coordinates of the intersection

(1) if car a starts from a certain place at a speed of 60km / h, write down the distance S1 (km) and its speed A and B trucks are driving on a highway at a constant speed. (1) If car a starts from a certain place at a speed of 60km / h, write the functional relationship between its driving distance S1 (km) and its driving distance t (H), and draw his image. (2) if car B starts from the same place 2 hours after car a starts and drives along the same direction at a speed of 80km / h, its driving distance S2 (km) is also a function of the driving time t (H) after car a starts, write its driving distance S2 (km) (3) find out the coordinates of the intersection of two images, and explain the practical significance of the coordinates of the intersection

（1）s1=60t
（2）s2=80（t-2）
(3) Point of intersection
The roots of two equations
t=8
s=480
Where and when do two cars meet

Traveling between a and B, the speed from a to B is 45km / h, and the speed from a to B is 60km / h. It takes 2.1h to go back and forth
Ask a question and solve it by equation

What is the distance AB?
Let AB distance be x km
X/45+X/60=2.1
7X/180=2.1
X=54
The AB distance is 54 km