Poly Operations + Factoring

What is the area for the given rectangle:

What is the perimeter for the given rectangle:

A square has a side length of x + 4. What is the area of the square?

A pool has a length of x - 5 and a width of x + 3. What is the area of the pool?

Find the area of the triangle with height (x+8) and base (2x+4). (A=1/2bh)

Which expression represents the perimeter of the triangle?

Find the volume of a rectangular prism with length (x+2), width (x-4), and height (2x+1). 

The perimeter of the triangle is 3x³ + 4x² + 8x + 15. If the shortest side is  2x² + 12x, the longest side (the hypotenuse) is x³ – 8x + 7, then what is the missing side length?