Calling all math wizzes! Could I please have a bit of mathematics help with this

[llamahorse]

Algebra 2? Thanks!!? I picked out all the problems and sequences of problems I wasn't sure of.. I'd appreciate any help you can give, preferably all but whatever you can will also suffice! If you could show the work for me so I can deduce what you did, or explain to me in writing what you did it would also be much appreciated!

here they are..

1:
27a(little 4 above the a on the right side) - 75a²
-----------------------------------------------------------
27a³ - 18a² -45a

for this part I have to simplify the expression that describes each function and then find the indicated value of the function..

2.
f(x)= x² - 25
----------------
2x²-7x-15

Find f(-4).

for these next two problems f(x) = 3x-8 and g(x) = x2+5
it asks to simplify the following...
3.
f(c)-f(10)
-----------
c-10

4.
f(x+12)-f(x)
--------------
12
then I have to simplify each rational expression in the next 2..

5.
x(little 4)-10x2+9
over
27-3x2

and finally..
6.
-3x-x²+4
over
x³+4x²-x-4