How to find area of a polygon i was gone today and dont understand it i will attatch picture of question

How do i do this? i don’t understand

The area of a rectangle is 10 cm^2. one side of the rectangle is x cm. express the perimeter of the rectangle in terms of x and show that this rectangle cannot have a perimeter of 12 cm. the perimeter of the rectangle in terms of x is __ cm

What is the solution to the division problem below x3+x2-11x+4/x+4