2x=3- 1
2x=2
x= 1
Substitute x= 1.
Then 1+3a=7.
3a=6
a=2
Substitute a=2.
You can find the value of x.
2、
There are x ships.
(x- 1)9=(x+ 1)6
9x-9=6x+6
9x-6x=6+9
3x= 15
x=5
(5- 1)x9=36 (name)
There are 36 students.
Suppose the speed of the plane is x km/h. ..
5 hours and 30 minutes =5.5 hours
(x+24)5.5=(x-24)6
5.5x+ 132=6x- 144
0.5x=276
x=552
(552-24) X6 = 3168km
A: The distance between the two cities is 3 168 km.
Let Xiao Ming's average speed in the first half hour be X km/h. ..
30 minutes =0.5 hours
0.5x+(0.5x2)x=30
0.5x+x=30
1.5x=30
x=20
A: Xiaoming's average speed in the first half hour is 20 kilometers per hour.
There seems to be a mistake in your second question. Please call me again. If you don't understand, please ask.