Answer:
C) 
Step-by-step explanation:

Recall the identity 
Answer: Benny started with 77 cards.
Step-by-step explanation:
The first step is to find what 43 is a half of. If we multiple 43 by two, we see that the answer is 86. As this number included the 9 cards he bought the day before, we must subtract 9 from 86, giving us 77.
46.2
you do 70/100=x/66
then cross multiply so (70•66)=100x
then you get 4620=100x
then you divide both sides by 100 and get x=46.2
6/12 can be reduced to 1/2.
6/6=1
12/6=2