The next few questions will reinforce your mastery of the Cartesian Coordinate System and of equations of straight lines. The distance between two points is obtained by the Pythagorean Theorem. The distance of a point $P$ from a line $L$ is the shortest distance between that point and a point on the line. Geometrically, you can obtain it by drawing a line through $P$ perpendicularly to $L$. It will intersect $L$ in a point $Q$ which is the point on $L$ closest to $P$. Once you have $Q$ you simply compute the distance $h$ between $P$ and $Q$. These concepts are illustrated in this Figure:

We will build slowly to a general formula for the distance of $P$ from $L$. Let's start with the line $L$ defined by $$y=\frac{1}{2}x+1.$$ The slope of $L$ is
$y =$ .
A line that's perpendicular to $L$ has the slope .
Hint: The slopes of two lines are negative reciprocals of each other.