Answer
Roberto is multiplying the same factor, (x+6)
with a greater number than Kelly,
so the resultant area of Roberto's plot will be greater than Kelly's.
Work Step by Step
In our calculations , at one point, the area of
Kelly's plot was expressed as $\quad (x+6)(x+2)$
and Roberto's as $\qquad (x+6)(x+3)$
Roberto is multiplying the same factor (x+6) with a greater number
than Kelly,
$(x+3)>(x+2)$,
so the resultant area of Roberto's plot will be greater than Kelly's.
