We have to calculate the difference of the given polynomials, we follows as:

After opening the brackets, the signs of all the terms changes as there is negative sign before the bracket.
=
Combining all the like terms, we get as
=
=
Option A is the correct answer.
T + b = 13...this is the seats....the number of trike seats + bike seats = 13
3t + 2b = 31....this is the wheels....number of trikes with 3 wheels + number of bikes with 2 wheels = 31 wheels
ur answer is A
Start from the end. 5+4*2. Which in turn equals 18 inches.