What is the ratio 812 in simplest form

Which expression is equivalent to the expression shown?

Which of the following is missing in the explicit formula for the compound interest geometric sequence below?

The scatter plot shows the number of animal cells clara examined in a laboratory in different months: plot ordered pairs 1, 20 and 2, 60 and 3,100 and 4, 140 and 5, 180 what is the approximate predicted number of animal cells clara examined in the 9th month?