#### Answer

$5x-y=-4$

#### Work Step by Step

Perpendicular lines have slopes that are negative reciprocals of each other.
The given line has a slope of $-\frac{1}{5}$.
This means that the slope of the line perpendicular to it is $5$.
Thus, the tentative equation of the line is $y=5x+b$.
The line is said to have a $y$-intercept of $4$ so $b=4$.
Therefore the equation of the line perpendicular to the given line is $y=5x+4$
Convert this to $ax+by=c$ form to have:
$y=5x+4
\\-5x+y=4
\\-1(-5x+y)=4(-1)
\\5x-y=-4$