Here are the properly formatted tasks:

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Simplify the following expressions:

1. [tex]4ab^3 \times (-3a^3b)[/tex]

2. [tex]\frac{6x^3 + 12x^3}{(3x)(2x^2)}[/tex]

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By simplifying the expressions and presenting the steps clearly, it becomes easier to read and understand the tasks.



Answer :

### Problem 3.1: Simplify [tex]\(4ab^3 \times -3a^3b\)[/tex]

To simplify the expression, follow these steps:

1. Multiply the coefficients: Multiply the numerical coefficients together.
[tex]\[ 4 \times -3 = -12 \][/tex]

2. Multiply the 'a' terms: Use the exponent addition rule [tex]\(a^m \times a^n = a^{m+n}\)[/tex].
[tex]\[ a \times a^3 = a^{1+3} = a^4 \][/tex]

3. Multiply the 'b' terms: Again, use the exponent addition rule [tex]\(b^m \times b^n = b^{m+n}\)[/tex].
[tex]\[ b^3 \times b = b^{3+1} = b^4 \][/tex]

4. Combine all results:
[tex]\[ 4ab^3 \times -3a^3b = -12a^4b^4 \][/tex]

So, the simplified form of [tex]\(4ab^3 \times -3a^3b\)[/tex] is:
[tex]\[ -12a^4b^4 \][/tex]

### Problem 3.2: Simplify [tex]\(\frac{6x^3 + 12x^3}{(3x)(2x^2)}\)[/tex]

To simplify the given rational expression, follow these steps:

1. Combine like terms in the numerator:
[tex]\[ 6x^3 + 12x^3 = (6 + 12)x^3 = 18x^3 \][/tex]

2. Simplify the denominator:
[tex]\[ (3x)(2x^2) = 3 \times 2 \times x \times x^2 = 6x^3 \][/tex]

3. Divide the simplified numerator by the simplified denominator:
[tex]\[ \frac{18x^3}{6x^3} \][/tex]

4. Cancel out the common factors in the numerator and denominator:
[tex]\[ \frac{18}{6} \cdot \frac{x^3}{x^3} = 3 \cdot 1 = 3 \][/tex]

So, the simplified form of [tex]\(\frac{6x^3 + 12x^3}{(3x)(2x^2)}\)[/tex] is:
[tex]\[ 3 \][/tex]

### Final Answers:

1. [tex]\(4ab^3 \times -3a^3b = -12a^4b^4\)[/tex]
2. [tex]\(\frac{6x^3 + 12x^3}{(3x)(2x^2)} = 3\)[/tex]