Hello,
Let's put the 6 houses on side: 6P9=9*8*7*6*5*4/6! = 84
For each choice there are 3! choices pour the other side
84*3!=504
If zero bus stops is an option, then it would be whole numbers. If the number of stops is greater than zero, it would be natural numbers.
Answer:
Step-by-step explanation:

You have to distribute the minus sign to the second parenthesis, changing the sign of every term:

Answer:
-33c+22d
Step-by-step explanation:
=(−11)(3c+−2d)
=(−11)(3c)+(−11)(−2d)