What is 820.5 in scientific notation

Bugs bunny was 33 meters below ground, digging his way toward pismo beach, when he realized he wanted to be above ground. he turned and dug through the dirt diagonally for 80 meters until he was above ground

Which of the following graphs could represent a quartic function?

According to the general equation for conditional probability if p(anb)=3/7 and p(b)=7/8 what is p(a i b)