It’s CD because it’s a longer line
Answer: 
Step-by-step explanation:
Given the following expression:

You need to substitute the given values of "a" and "b" into the expression. Notice that these values are:

Then;

Now you must solve the multiplications:

The final step is to add the numbers. Therefore, you get the following answer:

Answer:
E. 2.
F. 1.
Step-by-step explanation:
24 = 2 *2 *2 *3 * 1
2 = 2 * 1
So, comparing the 2 lists, the common factors are 2 and 1.