Multiplying Exponents
−16x5y3(−12)
192x5y3
21x4y6 / 35x4y4
3y2 / 5
What is the general form of an exponential growth equation?
y=a(1+r)x
What is the general form of an exponential decay equation?
y=a(1−r)x
What is the formula for compound interest?
A=P(1+r/n)n*x
x2(3y3)
3x2y3
24x7y7 / 40xy6
3x6y1 / 5
If a population starts at 500 and grows at a rate of 4% per year, what is the growth equation?
y=500(1+0.04)x
A car’s value is $20,000 and it loses 10% each year. What is the decay equation?
y=20000(1−0.10)x or y=20000(0.90)x
You invest $1,000 at 5% annual interest, compounded yearly. What is the equation?
A=1000(1+0.05/1)1*x or A=1000(1.05)x
14x4y5(−13xy3)
−182x5y8
30x4y6 / 20x3y2
3xy4 / 2
In the equation y=1200(1+.06)x, what does the 1.06 represent?
the growth factor (or 6% growth rate)
In the equation y=1500(0.85)x, what does 0.85 represent?
the decay factor (or 15% decay rate)
If interest is compounded quarterly, what does “n” equal in the formula?
4
−14x3y3(16x3)
−224x6y3
27x8y5 / 9x4y5
3x4
How many years will it take for an investment of $1,000 to grow to $2,000 at a 5% annual growth rate? (Round to the nearest year)
About 15 years
A phone loses 30% of its value each year. How much will a $600 phone be worth in 3 years?
$205.80
You invest $2,500 at 6% interest, compounded monthly for 3 years. What is the amount? (Round to nearest cent)
$2,993.48
−14x2y3(5x2y3)
−70x4y6
3x8y7 / 6x6y3
1x2y4 / 2
A bacteria culture triples every 7 hours. Write the growth equation if the starting amount is 80.
y=80(3)x/7
A radioactive substance halves every 12 hours. Write a decay equation starting with 100 grams.
y=100(0.5)t/12
A bank compounds interest daily. You invest $3,000 at 4.5% for 5 years. What is the final amount?
$3,762.89