Final answer:
Without the specific expressions, we can only explain the substitution process: Replace each variable in an expression with its given value and then simplify. This method is used to evaluate mathematical expressions with known variables.
Step-by-step explanation:
The given problem appears to involve evaluating expressions with known values for the variables a, b, c, and d. However, the expressions themselves are not included in the question. To provide a proper evaluation, each given expression should be substituted with a = -6, b = -4, c = 3, and d = 9 to find their respective numerical values.
As an example, if we had an expression like a + b + c + d, substituting the known values would give us -6 + (-4) + 3 + 9, which simplifies to 2.
Without the specific expressions to evaluate, we can only provide a generic explanation on how to substitute the variables with their values and simplify. Remember to always check that your answer is reasonable and that all terms are eliminated wherever possible to simplify the algebra.