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The problem of moving point in seventh grade mathematics
This problem examines coordinates and equations of motion, including the direction of velocity and multiple solutions.

(1) according to the meaning of the question, there are

X(p)=20-5t

X(q)=-4t

x(n)=-40+8t(t & lt; =5); x(n)=-8t+40(t & gt; 5)

(2) When n and q overlap for the first time:

-40+8t=-4t, so t= 10/3.

At this time, x (p) = 20-5 *10/3 =10/3.

The moment when n and q first overlap is:

-8t+40=-4t, so t= 10,

At this time, X(p)=20-5* 10=-30.

(3)

When t & lt=5, there is

-4t-(-40+8t)=20-5t-(-4t), and t = 20/1.

When t >; At 5 o'clock, yes

-8t+40-(-4t)=20-5t-(-4t), and t=20/3 is obtained.

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