## Calculus with Applications (10th Edition)

The line $$4x+3y=8$$ can be rewritten in slope-intercept form as $$y=-\frac{4}{3}x+\frac{8}{3}$$ so its slope is $-4/3$. The line $$4x+y=5$$ can be rewritten in slope-intercept form as $$y=-4x+5$$ so its slope is $-4$. The two lines do not have the same slope so they are not parallel.