## Algebra 1: Common Core (15th Edition)

y varies directly with x. The direct variation equation is $y = -2.5x$.
Find $\frac{y}{x}$ for each ordered pair. $\frac{y}{x}=\frac{-7.5}{3}=-2.5$ $\frac{y}{x}=\frac{2.5}{-1}=-2.5$ $\frac{y}{x}=\frac{-5}{2}=-2.5$ $\frac{y}{x}=\frac{-12.5}{5}=-2.5$ The ratio is $\frac{y}{x}=-2.5$ for each data pair. So y varies directly with x.