Final answer:
The fraction (b-4)/(b²-3b-54) can be rewritten as (b-4)/((b-9)(b+6)) by factoring the quadratic expression in the denominator. Without additional context, this is the equivalent fraction form.
Step-by-step explanation:
To write the fraction (b-4)/(b²-3b-54) as an equivalent fraction, it's necessary first to factor the denominator if possible. The denominator b²-3b-54 is a quadratic equation and can be factored into two binomial expressions. This quadratic can be factored as (b-9)(b+6), leading to the equivalent fraction:
\[(b-4)/(b²-3b-54) = (b-4)/((b-9)(b+6))\]
However, without additional context or requirements for the equivalent fraction, this is as far as one can go. If the goal is to cancel out terms or simplify the expression further, additional information or constraints are needed.