Final answer:
Jonah's error is that he calculated the perimeter of the rectangle incorrectly. The correct expression for the perimeter would be 4x or 5.25x.
Step-by-step explanation:
Jonah's error is that he calculated the perimeter of the rectangle incorrectly. To find the perimeter of a rectangle, you need to add up all the sides. In this case, the rectangle has two pairs of equal sides. Let's assume that the length of one of the sides is 'x'. So the correct expression for the perimeter would be 2x + 2x, which simplifies to 4x.
Since the given expression is 6 1/4x - 3, Jonah's error is the '- 3' term. The correct expression should be 6 1/4x. However, it's important to note that you can simplify this to 5 1/2x or 5.25x.