Hey there!!
How do we find the area of a rectangle?
Length * Breadth = Area
... Length * breadth = 55
Width is 6 miles less than the length.
... Width = Length - 6
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... Length ( Length - 6 ) = 55
... Length² - 6Length = 55
... Length² - 6Length - 55 = 0
... Length² + 5Length - 11Length - 55 = 0
... Length ( Length + 5 ) - 11 ( Length + 5 ) = 0
... ( Length - 11 ) ( Length + 5 ) = 0
... We could find two solution.
They are : 11 and -5.
As the values can not be in negatives, the appropriate length would be '11'
Length = 11
Breadth = Length - 6
... Breadth = 11 - 6
... Breadth = 5
Hence, the Length = 11 and the Breadth = 5
Hope my answer helps!