Algebra: A Combined Approach (4th Edition)

$-1$
Step 1: $\frac{x-3}{3-x}$ Step 2: $\frac{x-3}{-x+3}$ Step 3: $\frac{x-3}{-(x-3)}$ Step 3: Since the numerator and denominator both contain (x-3), they can be cancelled to give $\frac{1}{-1}$ Step 4: $\frac{1}{-1}$=$-1$