Step-by-step explanation:
the area of a rectangle is
length × width
that is in our case
(x + 3) × 4.5 = 4.5x + 4.5 × 3 = 4.5x + 13.5
remember, when multiplying 2 expressions, you multiply every term of one expression by every term of the other expression and then you add all these individual results up by considering the signs, of course.
