Question 933858
<pre>
There are many many, solutions.  Here are three:

-2,9,16 are in AP, with common difference 11 and subtracting
                    1,4,19, gives -3,3,-3 in GP, with common ratio -1.

-2,-5,-8 are in AP, with common difference -3 and subtracting 
                    1,4,19, gives -3,-9,-27 in GP, with common ratio 3.

-47,-68,-89 are in AP, with common difference -21, and subtracting 
                    1,4,19 gives -48, -72, -108, GP, with common ratio 1.5.

Edwin</pre>