Question

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

Answer 1

Answer:

Step-by-step 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

$y=(\frac{5}{8})^x$     $y=1(.625)^x$         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!