The rectangle has an area of .

Observe the figure:

The length of the rectangle is .

The width of the rectangle is .

Find the length.

Area of the rectangle is .

                  (Substitute , and )

                      (Distibutive property: )

  (Subtract from each side)

                 (Apply additive inverse property:)

        (Factors in the form of )

       (Take out the common factors)

                (Group of the common terms)

and       (Separate the equations)

and .             (Simplify)

Hence the lenght is always positive.

So, the length of the rectangle is .

Therefore, option (B) is right choice.

Option (B) is right choice.