Final answer:
When adding two negative numbers, the result is negative with the sum of their absolute values, and when subtracting a negative from a negative, it is like adding the positive equivalent. So, (-3) + (-6) = -9 and (-3) - (-6) = 3, which means the correct answer is option (b) -9, 3.
Step-by-step explanation:
When adding or subtracting negative numbers, we must follow specific rules for the operations. For addition, rule number 2 in our reference states that when two negative numbers are added together, the result will also be negative and their absolute values sum up. Therefore, (-3) + (-6) equals -9, since 3 + 6 is 9.
For subtraction, the fourth rule in our reference material indicates that we must change the sign of the number being subtracted and then perform the addition according to the rules. This means that (-3) - (-6) becomes (-3) + (+6) which simplifies to 3. This is because we subtract a negative which is the same as adding the positive equivalent (subtracting a debt is like gaining money).
Therefore, the answers to the student's question are :
- (-3) + (-6) = -9
- (-3) - (-6) = 3
Hence, the correct choice is (b) -9, 3