Answer is y = -1/2x + 1-1/2 for equation of line L
Step by step
Find slope using y2 - y1 over x2 - x1
-1 - 1 over 5 - 1 = -2/4 or simplified to -1/2
Now using point slope form, plug in one set of points (1, 1) and (m) slope of -1/2
y - y1 = m (x -x1)
y - 1 = -1/2 (x - 1)
Distribute multiply
y - 1 = -1/2x + 1/2
Add 1 to each side to isolate y
y -1 +1 = -1/2x + 1/2 + 1
Simplify
y = -1/2x + 1-1/2
That’s your equation of line L
You could also graph the two points and draw your line. Your slope is -1/2 (rise is -1 down, run is +2 right) and your y intercept is 1-1/2 where the line crosses the y axis.