Tìm hàm số f(x) thỏa mãn
a)\(f\left(x-1\right)+3f\left(\dfrac{1-x}{1-2x}\right)=1-2x,\forall x\ne\dfrac{1}{2}\)
b)\(f\left(x\right)+f\left(\dfrac{1}{1-x}\right)=x+1-\dfrac{1}{x},\forall x\ne0;x\ne1\)
c) \(3f\left(x\right)-2f\left(f\left(x\right)\right)=x,\forall x\in Z\)