Let's simplify and solve the expression:

$-\dfrac{5}{12} - \left(-\dfrac{9}{3}\right)$

1. Simplify $\dfrac{9}{3}$: $\dfrac{9}{3} = 3$

2. Substitute this back into the expression: $-\dfrac{5}{12} - (-3)$

3. Simplify the expression by eliminating the double negative: $-\dfrac{5}{12} + 3$

4. Convert $3$ to a fraction with a denominator of 12 to add the fractions: $3 = \dfrac{36}{12}$

5. Now add the fractions: $-\dfrac{5}{12} + \dfrac{36}{12} = \dfrac{-5 + 36}{12} = \dfrac{31}{12}$

So, the simplified result is:

$\dfrac{31}{12}$

Would you like more details or have any questions?

Here are 5 related questions you might find interesting:

1. How would you subtract $\dfrac{7}{15} - \left(-\dfrac{4}{5}\right)$?
2. What is the result of $-\dfrac{2}{3} + \dfrac{8}{9}$?
3. How do you add and subtract fractions with different denominators?
4. What is $\dfrac{5}{6} - \dfrac{2}{3} + \dfrac{1}{2}$?
5. How can you convert a mixed number to an improper fraction?

Tip: When adding or subtracting fractions, always make sure the fractions have a common denominator before performing the operation.