Answer
point-slope form: $y-4=-\frac{1}{2}(x-2)$
slope-intercept form: $y=-\frac{1}{2}x+5$
Work Step by Step
Step 1. Using the figure given in the exercise, we can see that line L is perpendicular to line $y=2x$; thus, we have its slope $m=-\frac{1}{2}$
Step 2. As the line passes the point $(2,4)$, we can write the line equation in point-slope form as $y-4=-\frac{1}{2}(x-2)$
Step 3.The above equation can be rewritten in slope-intercept form as $y=-\frac{1}{2}x+5$
