HURRY PLEASE
Solve the following system by the substitution method. Show your work.

{2x−7y=12
−x+3.5y=−6

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