Problem 3:
4x/(x+2) - 8/(x-1)
What I did:
Common denominator is: (x+2)(x-1)
4x(x-1)/(x+2)(x-1) - 8(x+2)/(x+2)(x-1)
[4x(x-1) - 8(x+2)]/(x+2)(x-1)
multiply the numerator out.
4x^2 -4x -8x-16
4x^2-12x-16 factor 4 out
4(x^2-3x-4)
factor
4(x-4)(x+1)
and that will reduce over the denominator.