## Elementary Geometry for College Students (6th Edition)

$\frac{-b}{a}$
(a,0) and (0,b) x1=a, y1=0,x2=0,y2=b Using slope formula m = $\frac{y2-y1}{x2-x1}$ m= $\frac{b-0}{0-a}$ = $\frac{-b}{a}$