If each photocopy of a manuscript costs 4 cents per page, what is the cost, in cents, to reproduce x copies of an x-page manuscript?

Question: If each photocopy of a manuscript costs 4 cents per page, what is the cost, in cents, to reproduce x copies of an x-page manuscript?

Solution:
Cost to reproduce 1 page of a manuscript = 4 cents
∴ Cost to reproduce x pages of a manuscript= 4x cents

Cost to reproduce x copies of a x page manuscript= x × 4x cents = 4x²cents