## Calculus with Applications (10th Edition)

$\frac{m-k}{km}$
$k^{-1}-m^{-1}$ 1. Use exponent rules (any expression raised to the power of -1 equals its reciprocal): $\frac{1}{k}-\frac{1}{m}$ 2. Find a common denominator (in this case it is km): $\frac{1\times m}{k\times m}-\frac{1\times k}{m\times k}$ 3. Simplify: $\frac{m}{km}-\frac{k}{km}$ 4. Combine fractions to get your answer: $\frac{m-k}{km}$