1. Calculate the sum of base lengths:
b_1 + b_2 = (3p - 6) + (2p + 5) = 5p - 1
2. Substitute the values into the volume formula:
V = \frac{1}{2} \times (5p - 1) \times (4p - 8) \times 18
3. Multiply by the constant terms:
V = \frac{1}{2} \times (5p - 1) \times (4p - 8) \times 18 = 9 \times (5p - 1) \times (4p - 8)
4. Use the distributive property to expand:
V = 9 \times (20p^2 - 40p - 4p + 8) = 9 \times (20p^2 - 44p + 8)
5. Distribute the 9:
V = 180p^2 - 396p + 72
So, the volume of the trapezoidal prism is:
V = 180p^2 - 396p + 72 \text{ cubic cm}