## Intermediate Algebra: Connecting Concepts through Application

2x+5y=20 5y=-2x+20 y=-$\frac{2}{5}$x+4 10x-4y=20 4y=10x-20 y=$\frac{5}{2}$x-5 These two lines have slopes that are opposite reciprocals of each other, therefore, the lines are perpendicular.