Question 123616
80*120=9,600 m^2 is the area of the factory.
therefore the total area of the factory & the parking lot must be: 2*9,600=19,200.
the formula for this problem is:
(80+2x)(120+2x)=19,200
9,600+240x+160x+4x^2=19,200
4x^2+400x+9,600-19,200=0
4x^2+400x-9,600=0
4(x^2+100-2,400)=0
4(x-20)(x+120)=0
x-20=0
x=20 answer for the width of the parking lot.
proof
(80+40)(120+40)=19,200
120*160=19,200
19,200=19,200