Find domain and range
a)f(x)= uderthe radical 1-3x
b)f(x)=1/2x-6
you know that the domain of √u is u>=0.
So, you need
1-3x >= 0
for the other, the domain is all reals except where the denominator is zero. So, where 2x-6=0, that value is excluded.
D = (-∞,3)U(3,∞)