Parallel lines have the same slope as each other...
First, get L in slope-intercept form:
5x-y+4=0
5x + 4 = y
y = 5x + 4 (5 is the slope and 4 is the intercept)
Now that we know the slope, we can use point-slope form to find the equation for the second line
y − y1 = m(x − x1)
y - (-3) = 5(x - (4))
y + 3 = 5(x - 4)
Get it into slope-intercept form...
y + 3 = 5x - 20
y = 5x - 17
This equation has the same slope as L and passes through the point (4, -3)