Answer :

Certainly! Let's take a detailed, step-by-step approach to solve these two expressions and verify their expansion.

### Expression 1: [tex]\((2x - 3y)(4x^2 + 6xy + 9y^2)\)[/tex]

We'll start by distributing [tex]\((2x - 3y)\)[/tex] across each term in [tex]\((4x^2 + 6xy + 9y^2)\)[/tex]:

1. First term: [tex]\(2x \cdot (4x^2 + 6xy + 9y^2)\)[/tex]
[tex]\[ 2x \cdot 4x^2 = 8x^3 \][/tex]
[tex]\[ 2x \cdot 6xy = 12x^2y \][/tex]
[tex]\[ 2x \cdot 9y^2 = 18xy^2 \][/tex]
Adding these, we get [tex]\(8x^3 + 12x^2y + 18xy^2\)[/tex].

2. Second term: [tex]\(-3y \cdot (4x^2 + 6xy + 9y^2)\)[/tex]
[tex]\[ -3y \cdot 4x^2 = -12x^2y \][/tex]
[tex]\[ -3y \cdot 6xy = -18xy^2 \][/tex]
[tex]\[ -3y \cdot 9y^2 = -27y^3 \][/tex]
Adding these, we get [tex]\(-12x^2y - 18xy^2 - 27y^3\)[/tex].

3. Combining all terms:
[tex]\[ (8x^3 + 12x^2y + 18xy^2) + (-12x^2y - 18xy^2 - 27y^3) \][/tex]

Simplify by combining like terms:
[tex]\[ 8x^3 + (12x^2y - 12x^2y) + (18xy^2 - 18xy^2) - 27y^3 = 8x^3 - 27y^3 \][/tex]

### Expression 2: [tex]\(4xy(2x - 3y)(2x + 3y)\)[/tex]

1. First, consider [tex]\((2x - 3y)(2x + 3y)\)[/tex]:

Notice that this expression is in the form of a difference of squares: [tex]\(a^2 - b^2 = (a - b)(a + b)\)[/tex].

Here, [tex]\(a = 2x\)[/tex] and [tex]\(b = 3y\)[/tex]:
[tex]\[ (2x - 3y)(2x + 3y) = (2x)^2 - (3y)^2 = 4x^2 - 9y^2 \][/tex]

2. Next, distribute [tex]\(4xy\)[/tex] across the result [tex]\(4x^2 - 9y^2\)[/tex]:

[tex]\[ 4xy \cdot 4x^2 = 16x^3y \][/tex]
[tex]\[ 4xy \cdot (-9y^2) = -36xy^3 \][/tex]

So, combining these, we get:
[tex]\[ 16x^3y - 36xy^3 \][/tex]

### Final Results:

1. For [tex]\((2x - 3y)(4x^2 + 6xy + 9y^2)\)[/tex]:
[tex]\[ 8x^3 - 27y^3 \][/tex]

2. For [tex]\(4xy(2x - 3y)(2x + 3y)\)[/tex]:
[tex]\[ 16x^3y - 36xy^3 \][/tex]

Thus, the expanded forms of the given expressions are:
[tex]\[ (2x - 3y)(4x^2 + 6xy + 9y^2) = 8x^3 - 27y^3 \][/tex]
[tex]\[ 4xy(2x - 3y)(2x + 3y) = 16x^3y - 36xy^3 \][/tex]