Question 1129326
<br>
The general form of an exponential equation is<br>
{{{f(x) = ab^x}}}<br>
Given f(8)=320 and f(26)=1200, we have<br>
{{{ab^8=320}}}
{{{ab^26=1200}}}<br>
Divide the 2nd equation by the first to eliminate a:<br>
{{{b^18 = 1200/320 = 15/4 = 3.75}}}
{{{b = 3.75^(1/18)}}}<br>
Use that value in either original equation to find the value of a:<br>
{{{a(3.75)^(8/18) = 320}}}
{{{a = 320/((3.75^(8/18)))}}} = 177.84 to 2 decimal places.<br>
We now have the a and b values for the exponential function.<br>
ANSWER: {{{f(x) = 177.84(3.75^(x/18))}}}<br>
Check on a graphing calculator:
f(8) = 320.0033
f(26) = 1200.0124<br>
The small error of course because of the rounding of the value of a.