We know that the volume of a rectangular prism is length*width*height. So for part a, we just need to multiply those values.
A:
[tex](8x-4)(x)(2.5x)\\(8x-4)(2.5x^2)\\20x^3-10x^2\\10(2x^3-x^2)[/tex]
So, the answer to part A is
10(2x³-x²)
For part B, all we do is plug 2 in for x into our polynomial.
[tex]10(2x^3-x^2)\\10(2(2)^3-(2)^2)\\10(16-4)\\10(12)\\120[/tex]
So, the volume is 120 cubic units.
Hope this helps!
