Given
An algebraic expression is the difference between seven times a number and three times that number.
To find:
The algebraic expression.
Solution:
Let x be the unknown number.
Multiplication is used for times and subtraction is used for difference.
7 times of a number = 7x
3 times of that number = 3x
The difference between seven times a number and three times that number is
Therefore, the algebraic expression for the given statement is 7x-3x and its simplified form is 4x.
Answer:
<em>The initial number of annual births in 2018 is 918,397</em>
<em>The percent decrease in birth rates is 2.37%</em>
<em>The expected number of births in 2021 is 834,379</em>
Step-by-step explanation:
<u>Exponential Decay Function</u>
The exponential function is frequently used to model natural decaying processes, where the change is proportional to the actual quantity.
An exponential decaying function is expressed as:
Where:
C(t) is the actual value of the function at time t
Co is the initial value of C at t=0
r is the decaying rate, expressed in decimal
We are given the function that models the annual birth rate for a population of a given country:
Where t represents the number of years since 2018.
a.) We can identify the variables with the actual model by comparing with the general equation, thus: Co=918,397 and 1-r=0.9763.
Solving for r we have r=1-0.9763=0.0237.
This means the initial number of annual births in 2018 (t=0) is 918,397
b.) The percent decrease in birth rates is r=0.0237 = 2.37%
c.) To find the expected number of births in 2021 (t=4 years), we substitute the value of t in the equation of the model:
Calculating:
y = 834,379
The expected number of births in 2021 is 834,379