I have the following equation, I want to solve it for b keeping a and c fixed.

5*b^5+(60-5a)*b^4+(125+50c-80a)*b^3+(594c-445a-775)*b^2+(2324c-1005a-3270)*b+3000c-750a-3000=0.

How to solve it in maple?

I have the following expression  f(t)=0.342 Dirac(t)+6.352 exp(-4t)+.0981 exp(-3.056t)  I want to convert it to a piecewise function of the form given below

 f(t)=0.342  if t=0

 f(t)=6.352 exp(-4t)+.0981 exp(-3.056t)      if t>0

when I applied                     convert(f(t),piecewise,t)

 I need help to plot  a sequence of the form given in the attachment below     

seq.docx    

a=5/6

then how to plot the function in Maple 12 

How to plot           f(n)=1/6                          if n=0

                                 =f(0).(1-a).a^{n-1}   if n=1,2,...  where 'a' is a given constant...