How do you find the decay factor?

To find the decay factor, you need to know the formula y=ab^x where "a" is the initial amount and "b" the growth or decay factor. It is a growth factor if the number next to "a" is bigger than 1, b>1, and it is usually in (). For example y=12(1.3)^x notice that (1.3) is bigger than 1 so it is a growth factor. The decay factor is "b" the same as growth factor but only that b<1.For example y=12(0.95)^x, 0.95 is less than 1 so it is a decay factor. In other Words, if the number in "b" is less than one it is decay factor, if bigger than one then it is a growth factor.