Answer :

To simplify the given expressions, let's break them down step-by-step.

### Simplifying [tex]\(\frac{11}{3(x-5)} - \frac{x+1}{3x}\)[/tex]

1. Find a common denominator:

For the fractions [tex]\(\frac{11}{3(x-5)}\)[/tex] and [tex]\(\frac{x+1}{3x}\)[/tex], the common denominator is [tex]\(3x(x-5)\)[/tex].

2. Rewrite each fraction with the common denominator:

[tex]\[ \frac{11}{3(x-5)} = \frac{11 \cdot x}{3x(x-5)} = \frac{11x}{3x(x-5)} \][/tex]

[tex]\[ \frac{x+1}{3x} = \frac{(x+1)(x-5)}{3x(x-5)} = \frac{x^2 - 5x + x - 5}{3x(x-5)} = \frac{x^2 - 4x - 5}{3x(x-5)} \][/tex]

3. Subtract the fractions:

[tex]\[ \frac{11x}{3x(x-5)} - \frac{x^2 - 4x - 5}{3x(x-5)} = \frac{11x - (x^2 - 4x - 5)}{3x(x-5)} \][/tex]

4. Simplify the numerator:

[tex]\[ 11x - (x^2 - 4x - 5) = 11x - x^2 + 4x + 5 = -x^2 + 15x + 5 \][/tex]

5. Write the final simplified expression:

[tex]\[ \frac{-x^2 + 15x + 5}{3x(x-5)} \][/tex]

### Simplifying [tex]\(\frac{-x^2 + 15x + 5}{3x^2 + [?]x}\)[/tex]

Given the missing term in the denominator, we assume it is zero as it is not specified:

1. Rewrite the denominator:

[tex]\[ 3x^2 + [?]x \Rightarrow 3x^2 + 0x = 3x^2 \][/tex]

2. Write the fraction with the simplified denominator:

[tex]\[ \frac{-x^2 + 15x + 5}{3x^2} \][/tex]

Therefore, the simplifications provide us with the following results:

### Final Simplified Expressions

1. The simplified form of [tex]\(\frac{11}{3(x-5)} - \frac{x+1}{3x}\)[/tex] is:

[tex]\[ \frac{-x^2 + 15x + 5}{3x(x-5)} \][/tex]

2. The simplified form of [tex]\(\frac{-x^2 + 15x + 5}{3x^2 + [?]x}\)[/tex] is:

[tex]\[ \frac{-x^2 + 15x + 5}{3x^2} \][/tex]

Both of these results match the expressions simplified above.