Answer:
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Step-by-step explanation:
The area of a rectangle can be calculated with the following formula:

Where "l" is the lenght and "w" is the width.
In this case we know that the length of a flowerbed is 4 times as long as its width. This can be expressed as:

We know that the width of the flowerbed is:

Therefore, substituting the width into
, we get that the length is:

Finally we can substitute the width and the lenght into the formula for calculate the area of a rectangle:
(or
)