Answer:
20
Step-by-step explanation:
The current area is 120(80)=9600 and he want to expand it by 4400 so that the new area will be 9600+4400=14000Â
14000=(120+x)(80+x)Â
14000=9600+200x+x^2Â
x^2+200x-4400=0Â
x^2-20x+220x-4400=0Â
x(x-20)+220(x-20)=0Â
(x+220)(x-20)=0, since x is an increase it must be greater than zero soÂ
x=20ftÂ
(120+20)(80+20)=14000ft^2