## Elementary Geometry for College Students (7th Edition)

First, we multiply both sides by 2: $2b = 27\times 2 - \frac{b}{2} \times 2 = 54 - b$ We add $b$ to both sides: $2b + b = 3b = 54$ Then, we divide both sides by 3: $b = 54\div 3 = 18$