Answer:
[tex]a_k=-5\cdot a_{k-1}, \,\,\,k=1,2,...\,\,\,\mbox{and}\,\,\,a_0=2[/tex]
Step-by-step explanation:
The recursion is as follows:
[tex]a_k=-5\cdot a_{k-1}, \,\,\,k=1,2,...\,\,\,\mbox{and}\,\,\,a_0=2[/tex]
and unrolling the first few examples:
[tex]a_0=2\\a_1=-5\cdot 2 = -10\\a_2= -5\cdot (-10) = 50\\a_3 = (-5) \cdot 50 = -250[/tex]