2.X- 1+X-2 = x+ 1+X。

Solution: X=7

3. The circumference of a rectangle is (7+6+6+5) * 2 = 48m.

So the speed of A is 4.8 and the speed of B is 3.2.

Two days after construction, Party A completed 9.6m, Party B completed 6.4m, * * * completed 16m.

There are still 32 meters left, and B needs to do 32/3.2= 10 days.

Or use the following equation:

It will take x days to complete this solution.

2( 1/ 10+2/ 15)+ 1/ 15X = 1

X= 10

A: It will take 10 days to complete.

Hope to adopt. This is the math class training of Jiangsu Education Edition. We did it. What a coincidence.