The owner of an office building is expanding the length and width of a parking lot by the same amount. the lot currently measures 120 ft by 80 ft, and the expansion will increase its area by 4,400 ft2. by how many feet should the length of the parking lot be increased?
a=lw

The best and most correct answer among the choices provided by your question is the second choice or letter B "20".

The current area is 120(80)=9600 and he want to expand it by 4400 so that the new area will be 9600+4400=14000 

14000=(120+x)(80+x) 

14000=9600+200x+x^2 

x^2+200x-4400=0 

x^2-20x+220x-4400=0 

x(x-20)+220(x-20)=0 

(x+220)(x-20)=0, since x is an increase it must be greater than zero so 

x=20ft 

(120+20)(80+20)=14000ft^2