A cube with side length [tex]$4p$[/tex] is stacked on another cube with side length [tex]$2q^2$[/tex]. What is the total volume of the cubes in factored form?

A. [tex](4p + 2q^2)(16p^2 + 8pq^2 + 4q^4)[/tex]
B. [tex](4p + 2q^2)(4p^2 - 8pq^2 + 2q^4)[/tex]
C. [tex](4p + 2q^2)(16p^2 - 8pq^2 + 4q^4)[/tex]
D. [tex](4p + 2q^2)(4p^2 - 8pq^2 - 2q^4)[/tex]



Answer :

To find the total volume of the two stacked cubes, we need to first calculate the volume of each cube individually.

1. Volume of the first cube:
- The side length of the first cube is [tex]\(4p\)[/tex].
- The volume [tex]\(V_1\)[/tex] of a cube is given by the formula [tex]\(s^3\)[/tex], where [tex]\(s\)[/tex] is the side length.
- Therefore, the volume of the first cube is:
[tex]\[ V_1 = (4p)^3 \][/tex]
- Calculating this, we get:
[tex]\[ V_1 = 64p^3 \][/tex]

2. Volume of the second cube:
- The side length of the second cube is [tex]\(2q^2\)[/tex].
- The volume [tex]\(V_2\)[/tex] of a cube is given by the formula [tex]\(s^3\)[/tex], where [tex]\(s\)[/tex] is the side length.
- Therefore, the volume of the second cube is:
[tex]\[ V_2 = (2q^2)^3 \][/tex]
- Calculating this, we get:
[tex]\[ V_2 = 8q^6 \][/tex]

3. Total volume:
- The total volume of both cubes stacked is the sum of the individual volumes:
[tex]\[ V_{\text{total}} = V_1 + V_2 \][/tex]
- Therefore, the total volume is:
[tex]\[ V_{\text{total}} = 64p^3 + 8q^6 \][/tex]

We are asked to express the total volume in factored form. Given the factored forms in the options, let's see which one matches [tex]\(64p^3 + 8q^6\)[/tex]:

[tex]\[ 64p^3 + 8q^6 = 8(8p^3 + q^6) \][/tex]

None of the provided options factor the polynomial [tex]\(64p^3 + 8q^6\)[/tex] in a straightforward manner. However, examining the forms, we can compare coefficients:

- We take the first expression and expand it to compare:

[tex]\[ (4p + 2q^2)(16p^2 - 8pq^2 + 4q^4) \][/tex]
Expanding this:
[tex]\[ (4p + 2q^2)(16p^2 - 8pq^2 + 4q^4) = 4p(16p^2 - 8pq^2 + 4q^4) + 2q^2(16p^2 - 8pq^2 + 4q^4) \][/tex]
[tex]\[ = 64p^3 - 32p^2q^2 + 16pq^4 + 32p^2q^2 - 16pq^4 + 8q^6 \][/tex]
[tex]\[ = 64p^3 + 8q^6 \][/tex]
This is equal to our total volume [tex]\(64p^3 + 8q^6\)[/tex].

Thus, the factored form that correctly represents the total volume is:

[tex]\[ \left(4 p+2 q^2\right)\left(16 p^2-8 p q^2+4 q^4\right) \][/tex]

Therefore, the correct option is:
[tex]\[ \boxed{\left(4 p+2 q^2\right)\left(16 p^2-8 p q^2+4 q^4\right)} \][/tex]