Exponential Equations and Expressions – Day 2. Key Concepts. Another form of the exponential equation is
, where a is the initial value, r is the rate of growth or decay, and t is the time. This formula is used when repeatedly finding increases or decreases based on a PERCENTAGE (%).
Initial value= 6000
Time = 5 years
Rate of increase = 4% = .04
There will be about 4892 residents.
Initial value= 10
Time = 3 scans
Rate of decrease = 15% = .15
The 10 in picture frame is reduced to 6.14 inches
Sometimes, interest is compounded more often than once a year. Some common examples are when interested is compounded quarterly (4 times a year) or monthly (12 times a year). If this is the case, the formula may look slightly different ,
where n is the only new variable representing the number of times compounded.
be in the account after 5 years.
Determine your variables: a = 600 r = .04
n = 12 t = 5
Substitute these values into the equation and solve for y.
y = _______________
of values by substituting
values into the equation
for x and solving for y.
Total of residents
25 50 100 150 200 250
# of years