The sides of a rectangle are (3x + 5) cm and (8x + 4) cm. Which expression represents its area?
Note
Area of a rectangle is length × width. Multiply every part: (3x)(8x) = 24x^2, outside and inside terms add to 52x, and 5×4 = 20. So the area is 24x^2 + 52x + 20.