y=(x-1/3-8/3)/(3x-1) y=1/3-8/(9x-3) y-1/3=-8/(9x-3) 9x-3=-8/(y-1/3) 9x=-8/(y-1/3)+3 9x=(3y-9)/(y-1/3) x=(y-3)/(3y-1) 反函数与原函数相同定义域3x-1≠0
