Answer :

Sure, let's solve the problem step by step by expanding the given binomial expression [tex]\((x^{3n} + y^{3m})^3\)[/tex].

To expand [tex]\((a + b)^3\)[/tex], we use the binomial theorem, which is written as follows:
[tex]\[ (a + b)^3 = a^3 + 3a^2b + 3ab^2 + b^3 \][/tex]

In our case, we let:
[tex]\[ a = x^{3n} \quad \text{and} \quad b = y^{3m} \][/tex]

Substituting these into our binomial expansion formula, we get:
[tex]\[ (x^{3n} + y^{3m})^3 = (x^{3n})^3 + 3(x^{3n})^2(y^{3m}) + 3(x^{3n})(y^{3m})^2 + (y^{3m})^3 \][/tex]

Now we need to simplify each term individually:

1. For [tex]\((x^{3n})^3\)[/tex]:
[tex]\[ (x^{3n})^3 = x^{3n \cdot 3} = x^{9n} \][/tex]

2. For [tex]\(3(x^{3n})^2(y^{3m})\)[/tex]:
[tex]\[ 3(x^{3n})^2(y^{3m}) = 3(x^{3n \cdot 2})(y^{3m}) = 3(x^{6n})(y^{3m}) = 3x^{6n}y^{3m} \][/tex]

3. For [tex]\(3(x^{3n})(y^{3m})^2\)[/tex]:
[tex]\[ 3(x^{3n})(y^{3m})^2 = 3(x^{3n})(y^{3m \cdot 2}) = 3(x^{3n})(y^{6m}) = 3x^{3n}y^{6m} \][/tex]

4. For [tex]\((y^{3m})^3\)[/tex]:
[tex]\[ (y^{3m})^3 = y^{3m \cdot 3} = y^{9m} \][/tex]

Combining all these terms together, we get:
[tex]\[ (x^{3n} + y^{3m})^3 = x^{9n} + 3x^{6n}y^{3m} + 3x^{3n}y^{6m} + y^{9m} \][/tex]

So, the expanded form of [tex]\(\left(x^{3n} + y^{3m}\right)^3\)[/tex] is:
[tex]\[ x^{9n} + 3x^{6n}y^{3m} + 3x^{3n}y^{6m} + y^{9m} \][/tex]