CAS Multiplication

[rushfan]

I have the following cas expression:

1/s +(0.171/(s+7.854) -0.171/(s+1.146))

How can put the expression under a common simplified denominator?

If I write:

collect(1/s +(0.171/(s+7.854) -0.171/(s+1.146)))

it will display:
(s+6.45953750494)*(s+1.39339449506)/(s*(s+7.854)*(s+1.146))

How can I make it distribute the s?

That is, put the expression in the form:

like (b1*s^2 +b2*s +b3)/(a1*s^4+ a2*s^3 + a3*s^2 +a4*s +a5)

If I write (s+1)*(s-1) I can't ever make it display (s^2 -1).

Simplifying does not do what I expect.