To simplify, we can factor the numerator and denominator separately.
Numerator:
x^2 - 64 can be factored as (x + 8)(x - 8).
Denominator:
x^2 - 9x can be factored as x(x - 9).
The expression becomes:
((x + 8)(x - 8))/(x(x - 9)) * (x + 9)/(x^2 + x - 72)
Next, we can cancel out common factors:
(x + 8)(x - 8)/(x(x - 9)) * (x + 9)/((x - 8)(x + 9))
The (x + 8) terms and (x + 9) terms cancel out:
1/(x(x - 9))
Therefore, the expression simplifies to 1/(x(x - 9)).