Given:
Given that the length of the rectangle is 5x + 2.
The width of the rectangle is x - 4.
We need to determine the area of the rectangle in a simplified polynomial expression.
Area of a rectangle:
The area of the rectangle can be determined using the formula,
![A=length * width](https://img.qammunity.org/2021/formulas/mathematics/middle-school/cl4w9ehtu2u8vzmpt5egfg2tazb5r5zhhy.png)
Substituting length = 5x + 2 and width = x - 4, we get;
![A=(5x+2)(x-4)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ex5hzxvui051kw75bufb65qvpq4jv7gyw5.png)
Multiplying the terms, we have;
![A=5x^2-20x+2x- 8](https://img.qammunity.org/2021/formulas/mathematics/middle-school/phcqrcxuxkjh2ufta8sye4iypgvycxefk1.png)
Adding the like terms, we get;
![A=5x^2-18x- 8](https://img.qammunity.org/2021/formulas/mathematics/middle-school/21tvk69egiqdikdu4rdmxxkqbm1lnlkc4d.png)
Thus, the area of the rectangle is
![5x^2-18x-8](https://img.qammunity.org/2021/formulas/mathematics/middle-school/7j1xcyjvugtca1e3gctnd1jqadyuiblpuj.png)
Hence, Option c is the correct answer.