Question 944631
1:


Why should the area expression need to be factored?  Factoring will only give two rectangular dimensions, but the garden can have many other dimensions.
Maybe you only care about   (x+7) and (x-6).



2:


Difference of areas.
Yard is {{{6x*10x=60x^2}}}, and pool area is {{{pi*(2x)^2=pi*4*x^2}}}.
Amount of yard remaining,  {{{60x^2-4pi*x^2}}}.