The population of a certain animal species you are studying decreases at a rate of 3.5% per year. only 80 of the animals in the habitat remain after 3 years of conducting your research. what was the initial amount of animals

The function:

f ( x ) = x * 0.965^t

where x is the initial amount and t is the number of the years

80 = x * 0.965^3

80 = x  *  0.89632

x = 80 : 0.89632 ≈ 89

The initial amount of animals was 89.

  or  

step-by-step explanation:

if the four friends split the cost, p, of the pizza evenly, then each friend pays one-fourth of the cost of the pizza.

the expression is   or