Pythagorean theorem
c2 = a2 + b2
71^2 = 43^2 + b2
5041 = 1849 + b2
3192 = b2
b = 56.5 which is answer choice d
According to the information given in the exercise, the following expression represents the area of the rectangular garden:

And the following expression represents the combined area of the walkway around the rectangular garden and the area of the garden:

You can identify that the word "combined" indicates that that expression was obtained by adding both areas.
Knowing the above, you can set up the following equation:

Where "A" is the area of the walkway around the rectangular garden.
Solving for "A", you get the following expression:

The answer is:
6x^2 -7x + 2 with a factor of 2x -1
If you divide the trinomial by the factor you will get the other factor.
See attachment