Final answer:
To find the perimeter of a rectangle with a given length and area, first find the width by dividing the area by the length. Then, use the formula P = 2(length + width) to find the perimeter.
Step-by-step explanation:
To find the perimeter of a rectangle, you need to add up all the sides. In this case, the length of the rectangle is given as 2x + 3 units. To find the width, we can divide the area (2x² - 5x - 12) by the length. This will give us the width as (2x^2 - 5x - 12)/(2x + 3) units. Once we have the length and width, we can use the formula P = 2(length + width) to find the perimeter. Plugging in the values, we get P = 2(2x + 3 + (2x² - 5x - 12)/(2x + 3)). You can simplify this expression further to get the final answer.