The equation of the line that passes through (5, -4)
and is perpendicular to line y = 1/5x + 4
is y= -5x + 21
The slope that is perpendicular to the slope 1/5x is -5x.
To find a perpendicular slope, you take the negative reciprocal.
The negative reciprocal of 1/5x is -5/1x, or -5x
However, y = -5x + 4 does NOT pass through (5, -4)
Looking at the line on a graph, we can find that if the y-intercept is 21, it DOES pass through (5, -4)