The length and width of the garden are 47 ft and 21 ft respectively.
Step-by-step explanation
Suppose, the width of the garden is
feet.
As the garden is 5 feet longer than twice its width, so the length will be:
![(2x+5) feet](https://img.qammunity.org/2019/formulas/mathematics/high-school/ms4zsf6yfjh55j99cz6pao9usfmzy22cfj.png)
So, the area of the garden
![= length*width=x(2x+5)ft^2](https://img.qammunity.org/2019/formulas/mathematics/high-school/ls9014okxwxg0a5uxdvqwy4hij4pamalnw.png)
Now, the garden has a sidewalk 3 feet wide on two of its sides. That means, the length of the garden including the sidewalk
and the width including the sidewalk
![=(x+3)ft](https://img.qammunity.org/2019/formulas/mathematics/high-school/l2lgsowqphzswqifcgrjn9xj77n8acsqig.png)
Given that, the area of the sidewalk is 213 ft². So the equation will be.....
![(2x+8)(x+3)-x(2x+5)=213\\ \\ 2x^2+14x+24-2x^2-5x=213\\ \\ 9x+24=213\\ \\ 9x=189\\ \\ x=(189)/(9)=21](https://img.qammunity.org/2019/formulas/mathematics/high-school/3aovtlblolhcyq8w0t2se0iehagavi0u6d.png)
So, the width of the garden is 21 feet and the length is
![(2*21+5)ft= 47 ft](https://img.qammunity.org/2019/formulas/mathematics/high-school/rlo0j4pp883yitu50jmjz05ubtjffwkroo.png)