[s3a]

Q: How does a catalyst affect equilibrium?

A: A catalyst will only increase the rate of reaction of a system not yet at equilibrium.

Once at equilibrium, the system will no longer be affected.

(WHAT DOES THE FOLLOWING MEAN?) In addition, the system will try to resist change from the equilibrium positive.
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1) What's an equilibrium positive??
2) How does a system "resist change"? (I don't get that concept at all)

Any help would be greatly appreciated!

[cliverlong]

Q: How does a catalyst affect equilibrium?

A: A catalyst will only increase the rate of reaction of a system not yet at equilibrium.

I wouldn't write it like that.
I would write
The catalyst increases the rate of both forward and back reactions so that the equilibrium point is reached faster than the uncatalysed reaction. The catalyst has no effect upon the position of equilibrium - that is the relative amounts of product and reactants.
See here
http://www.chemguide.co.uk/physical/equilibria/introduction.html#top
for a clear explanation of this dynamic equilibrium state and the route to reach it

Once at equilibrium, the system will no longer be affected.

No.
At equilibrium the overall reaction quantities are not changing but the reaction proceeds, reactants react and products turn back into reactants

(WHAT DOES THE FOLLOWING MEAN?) In addition, the system will try to resist change from the equilibrium positive.
1) What's an equilibrium positive??

Never heard of the term before.
From the context of your question I would replace "equilibrium positive" with "state of dynamic equilibrium"

2) How does a system "resist change"? (I don't get that concept at all)

A new idea has been introduced - that is Le Chatelier's principle. Read
http://www.chemguide.co.uk/physical/equilibria/lechatelier.html#top

Any help would be greatly appreciated!

[cliverlong]

1) What's an equilibrium positive??

Maybe you misread or mistyped. Maybe you meant
"equilibrium position"
The links I have posted above will explain the term

Clive