Can someone please show and explain how you got the answer for these please ​

Can someone factor this fully? my friend and i have two different answers and i would like to know if either of them is right. you in advance. a^2 - b^2 + 25 + 10a

Due to a packaging error, 4 cans labeled diet soda were accidentally filled with regular soda and placed in a 12 pack carton of diet soda. two cans were randomly selected from this 12 pack. what is the probability that both cans were regular soda?

Peyton's field hockey team wins 4 games out of every 7 games played. her team lost 9 games. how many games did peyton's team play?