Step-by-step explanation:
since the area of a rectangle is
area = length × width
so,
length = area / width
(x² - 120x + 2700) / (x - 30)
so, let's do an expression division (very similar to a numeric division) :
x² - 120x + 2700 / x - 30 = x - 90
- x² - 30x
---------------------------
0 - 90x + 2700
- - 90x + 2700
‐-----------------------------
0 0
the length in feet is : x - 90
