Verified answer

4/(x+2) = y /(x+2)(x+1)

4/(x+2) times (x+2)(x+1) = y

4(x+1) = y

y = 4x + 1

4x/(x-1) = y /(x+1)(x-1)

4x/(x-1) times (x+1)(x-1) = y

4x(x+1) = y

y = 4x^2 + 4

If 4x/(x-1) = y (x+1) (x-1)

4x/(x-1) times 1/ (x+1)(x-1) = y

4x / (x+1) (x^2-1) = y

y = 4x / (x^3 +x^2-x-1)

Ok....