Question

Determine model represents exponential growth or exponential decay. Then identify the initial amount and the percent increase or decrease

Answer 1

Explanation:

Think of each of these in terms of the standard form of the exponential equation:

`y=a(b)^x`

where a is the initial amount and b is the percent increase or decrease. First off, the exponent is on the b, the increase or decrease. It is not on the a value. Second, if b is a decimal less than 1 or is a fraction less than 1, it is a decrease. To find the percent increase or decrease, move the decimal 2 places to the right.

Original problem rewrite Initial amount %inc/dec

`y=(1.2)^x`
`y=1(1.2)^x` 1 120% inc

`y=(.78)^x`
`y=1(.78)^x` 1 78% dec

`y=((5)/(8))^x`
`y=1(.625)^x` 1 62.5% dec

`y=28(1.03)^x` N/A 28 103% inc

`y=25,000(.95)^x` N/A 25,000 95% dec

`y=(2)^x`
`y=1(2)^x` 1 200% inc

Hopefully that helps!