Because A= 10 B=8, (3A-B)=22 people.

Half of the people get off the bus halfway, so 22*0.5= 1 1 person.

So there are 1 1 people left in the car.

(8A-5B)=40 people (there are * * * people after getting on the bus)

40- 1 1=29 people (boarding number)

the second question

Is there something wrong with your question ~ Is it the result of A-XY-2YZ+3SZ or the correct result of A-(XY-2YZ+3XZ)?

Because a-xy-2yz+3sz+(xy-2yz+2xz) = 2xy-3xy+2yz.

a-XY-2YZ+3SZ = 2XY-3XY+2YZ-(XY-2YZ+2XZ)

a-XY-2YZ+3SZ = 2XY-3XY+2YZ-XY+2YZ-2XZ

=4YZ-2XY-2XZ