## College Algebra 7th Edition

To determine if the lines are parallel, we compare their slopes. The line $y=-\frac{1}{3}x-1$ has a slope $-\frac{1}{3}$. We need to find the slope of the line $9y+3x+3=0$: $9y+3x+3=0$ $9y=-3x-3$ $y=- \frac{1}{3}x-\frac{1}{3}$ So this line has a slope of $-\frac{1}{3}$. Since the slopes are the same, the lines are parallel.