Chapter 7 - Rational Functions - 7.3 Multiplying and Dividing Rational Expressions - 7.3 Exercises - Page 580: 15

$= -\frac{(k+6)}{(k+9)} $

$\frac{(k+5)(7-k)}{(k-7)(k-3)} \times \frac{(k-3)(k+6)}{(k+9)(k+5)}$ $= \frac{(k+5)(7-k)(k-3)(k+6)}{(k-7)(k-3)(k+9)(k+5)} $ $= \frac{(7-k)(k-3)(k+6)}{(k-7)(k-3)(k+9)} $ $= \frac{(7-k)(k+6)}{(k-7)(k+9)} $ $= \frac{(-(k-7))(k+6)}{(k-7)(k+9)} $ $= \frac{-(k+6)}{(k+9)} $ $= -\frac{(k+6)}{(k+9)} $