Can someone solve this problem for me and show in the comments step by step

Question 5 spring semester final exam math evaluate

Explain how you do each step what term makes it inconsistent y=2x - 4 ?

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