Exponential Percent Growth

Rhonda deposited $3000 in an account in the Merrick National Bank, earning 4.2% interest, compounded annually. She made no deposits or withdrawals. Write an equation that can be used to find B, her account balance after t years.

• B = 3000(1 – 4.2)^t

• B = 3000(1 + 4.2)^t

• B = 3000(1 – 0.042)^t

• B = 3000(1 + 0.042)^t

A student invests $500 for x years in a savings account that earns 4% interest per year. No further deposits or withdrawals are made during this time. Write an function f(x) to represent the amount of money earned after x years.

• f(x) = 500 (.60)^x

• f(x) = 500 (.96)^x

• f(x) = 500 (1.04)^x

• f(x) = 500 (1.4)^x

y= 50(1.07)^x

Is this growth or decay?

• growth

• decay

• neither

What is the percent growth?

• 50%

• 1.07%

• 107%

• 7%

What is the initial amount?

• 1000

• 0.65

• 165

• 65

y = 0.5 (1.081)^x

^{What is the initial amount}

• 1.081

• 108.1

• 8.1

• 0.5

y = 0.5 (1.081)^x

^{Is this growth or decay}

• growth

• decay

• neither

y = 0.5 (1.081)^x

^{What percent did it grow?}

• 0.5

• 1.081

• 108.1

• 8.1

• 81

y = 240(1.0375)^x

^{What is the percent growth?}

• 1.0375

• 375%

• 37.5%

• 3.75%

• The exponent.

• The rate of growth or decay of a function.

• The initial value, or y-intercept of the graph.