Question 798837
Area = length x breadth
Here Area = a*b = (a-6)*(b+8) = (a+6)*(b-4)
ab = ab+8a-6b-48 = ab-4a+6b-24
Subtract ab from each
4a=3b+24
And 
4a=6b-24
These are equal
3b+24=6b-24
48=3b
b=16
a=18
Rectangle is 18 x 16 ft

Check 
Area1=16*18=72*4
Area2=12*24
Area3=24*12