<span>b. 4+12÷2=4+6=10
c. (20–5)•3=15•3=45</span>
40 because 3+6+12 = 21 and 8+11+21 =40
Hello! First insert 6 where the h is located. So we have an equation that looks like the following.
Although you could leave the equation in its original form, I am going to switch it around.
Move the 6 to the other side and do the math
Factor and after factoring your T will be as followst =

= -0.1900
t =

= 1.315
383882818199102039992919(
An exponential model can be described by the function

where: a is the initial population or the starting number, b is the base and x is the number of periods elapsed.
When the base of an exponential model is greater than 1 it is called a growth factor, but when it is less than 1 it is called a decay factor.
Given the exponential model

n is the final output of the exponential model, 20.5 is the starting number, 0.6394 is the base and t is the number of periods/time elapsed.
Here, the base is 0.6394 which is less than 1, hence a decay factor.
Therefore, <span>the
base, b, of the exponential model is 0.6394; It is a
decay factor.</span>