factored the expression 2x^4+2x^3-x^2-x. His work is shown. At which step did make his first mistake, and which statement describes the mistake?

You have 2 sides that are 2 cms and you have 6 sides that are 1/2 cm and you have 4 sides that are 1 cm. the smallest sides are 1/2 the medium sized sides are 1 and the smallest are 1/2. so to find the perimeter you have to add them all up together so your answer will be 11 cm's