I need help with 9 - 14

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

Which of the following equations is equivalent to x/3-6/x=1

Find the unit rate. enter your answer as a mixed number. a fertilizer covers 2/3 square foot in 1/2 hour.