Let the speed of point B be x, and point A and point B start at the same time and move in opposite directions, then their time is equal.

Yes: 8/2=4/x

The solution is x= 1.

Therefore, the moving speed of point B is 1.

Let the elapsed time be t.

Then B is in front of A, and the distance traveled by point B-the distance traveled by point A =6, then

2t-t=6, and t=6 is obtained.

A is in front of B, the distance traveled by point A-the distance traveled by point B =6, then

2t-t= 12+6, and the solution is t= 18.

number axis

Is a specific geometric figure. A straight line is a collection of countless points, and there are countless real numbers including positive real numbers, zero real numbers and negative real numbers. Because of their * * * nature, they use countless points on a straight line to represent real numbers. At this time, a straight line with origin, positive direction and unit length is used to represent real numbers. When the right side is defined as the positive direction, the number represented by the upper point on the right side of two numbers on this straight line is always greater than the number represented by the upper point on the left side, positive numbers are greater than zero, and zero is greater than negative numbers.