Answer: 9 + 3x
Explanation:
Since the shape of the banner is a rectangle, we know that the equation for area = length * width. I would say that the length is 3+x and the width is 3. Now, we simply just have to use multiplication with distribution to solve.
3(3+x) = 9+3x (also can be written as 3x+9)
**simplest form means no parenthesis**
hope this helps!