Answer:

Step-by-step explanation:
Step 1:
Write the expression

Step 2: Expand 

Step 3: Collect similar terms

Step 4: Factor 4 out of the expression to prove that the expression is a multiple of 4.

I don't know what you mean by unknown factor but a quotient is the answer of a division problem
Answer:
14
Step-by-step explanation:
Replace with the values
15-1/2(2) = 15-1 = 14