Question 1197442
<br>
y = ab^x<br>
The two given points give us<br>
(1) {{{-4=ab^(-1)}}}
(2) {{{-0.5=ab^2}}}<br>
Divide (2) by (1) to get<br>
{{{b^3=1/8}}}
{{{b=1/2}}}<br>
Use that value in either (1) or (2) to find a.<br>
{{{-4=a(1/2)^(-1)=2a}}}
{{{a=-2}}}<br>
ANSWER: {{{y=ab^x=(-2)(1/2)^x}}}<br>