Exponential Growth & DecayMod 7 Lesson 6 Review

End amount𝒚=𝒂𝒃𝒙

Beginningamount

Growth Factor if b > 1 ORDecay Factor if 0<b< 1 Time

Remember, to find your growth or decay factor:b = 1 + rateRate must be written as a decimal. From % to decimal, you will need to move the decimal 2 places to the left. For example, 6.8% would be 0.068.

 If the value of the house is decaying at 37%, our decay factor would be: b=1-.37=.63

If a population is growing at 7%, our growth factor would be: b=1+.07 = 1.07

On your 10th birthday, you invested $235 in an account that pays 7.5% annually. You are planning to withdraw the money on your 18th birthday. How much money will be in the account?• Initial amount: a=235• Rate as a decimal: r=.075• Growth factor: b=1+.075=1.075• Time: t=8

= $419.12