Find the derivative. Simplify as much as possible.
s(x)=(9-12x)/[(x/3)-(1/4)]
your function simplifies down to
s(x) = -36 , x not equal to 3/4
so the derivative is zero.
s(x)=(9-12x)/[(x/3)-(1/4)]
s(x) = -36 , x not equal to 3/4
so the derivative is zero.