Chapter 7 - Section 7.4 - Adding and Subtracting Rational Expressions with Different Denominators - Exercise Set - Page 516: 46

$\frac{1-2y}{2x+2y}$

Step 1: $\frac{1}{2x+2y}-\frac{y}{x+y}$ Step 2: $\frac{1\times1}{(2x+2y)\times1}-\frac{y\times2}{(x+y)\times2}$ Step 3: $\frac{1}{2x+2y}-\frac{2y}{2x+2y}$ Step 4: $\frac{1-2y}{2x+2y}$ Step 5: No further simplification possible, so the answer is $\frac{1-2y}{2x+2y}$