## College Algebra (10th Edition)

$\color{blue}{y=4}$
RECALL: (1) A vertical line has an equation $x=h$ where $h$ is the x-intercept. Every point on this line has $x=h$. (2) A horizontal line has an equation $y=k$ where $k$ is the y-intercept. Every point on this line has $y=k$. (3) A vertical line and a horizontal line are perpendicular to each other. The line we are looking for is perpendicular to the vertical line $x=8$. This means that the line we are looking for is horizontal. Since the line contains the point $(3, 4)$, then every point on the line has $y=4$. Thus, the equation of the line we are looking for is: $\color{blue}{y=4}$