A sample of a radioactive isotope had an initial mass of 540 mg in the year 2009 and decays exponentially over time. A measurement in the year 2011 found that the sample's mass had decayed to 300 mg. What would be the expected mass of the sample in the year 2021, to the nearest whole number?

Ibelieve a is the correct answer because 3 is the y-intercept you can see it from the graph. so from here the answers could only be a and c. they are differently at the sign.substitute x with 1so the equation for a is 3*(1.4)^x3*(1.4)^1 = 4.2look back at the graph it is true that when x= 1 y= 4.2if you use equation from c. when x= 1 then y will be negative number which is falseso correct answer is a

2,4,5,8,10 are divisible by 40