giai các phương trình sau:
a,\(\frac{1-x}{2013}=1+\frac{2-x}{2012}-\frac{x}{2014}\)
b,\(\frac{2-x}{2001}-1=\frac{1-x}{2002}-\frac{x}{2003}\)
c,\(\frac{x-a-b}{c}+\frac{x-b-c}{a}+\frac{x-a-c}{b}=3\)
d,(x+3)4 + (x+5)4=16
e,x4+ 3x3 - 7x2- 27x-18=0
f,\(\frac{2-x}{2001}-1=\frac{1-x}{2002}-\frac{x}{2003}\)