Answer:
![2.5x^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/e07p2ypula44rk6t15cdwuu4zz5wor4qb2.png)
Explanation:
Let x be the shorter side of the rectangle, which is also its width (w), so:
![w=x](https://img.qammunity.org/2023/formulas/mathematics/college/78ysi9yu6z2go3oslo6o0whypm647sjbs1.png)
Given that the length of the rectangle is two-and-a-half times its width, this means the length (l) can be expressed as:
![l=2.5x](https://img.qammunity.org/2023/formulas/mathematics/high-school/619gmt3n4erwfcwsp9c6ren2vhli2wwub5.png)
The area of a rectangle (A) is the product of its length (l) and width (w):
![A =l \cdot w](https://img.qammunity.org/2023/formulas/mathematics/high-school/j6m70ogeobs4ns29n3lztgph1nfuyu6gkc.png)
Substitute the expressions for length and width into the formula for area:
![A=2.5x \cdot x](https://img.qammunity.org/2023/formulas/mathematics/high-school/inujbbpz7jccbs8uu6xz2lhdy4w4ucv6qd.png)
Simplify this expression:
![A=2.5x^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/k2t5irlwyyxc9zg5qo1o3kyol3mxtrb2ox.png)
Therefore, the expression for the area of the rectangle in terms of x is:
![\Large\boxed{\boxed{2.5x^2}}](https://img.qammunity.org/2023/formulas/mathematics/high-school/j2537gli06sy4kjg6t8swjwli1lk2u2vhj.png)