Change both equations into slope-intercept form.
5x + 4y = 1
4y = 1 - 5x
y = 1/4 - 5/4x
y = -5/4x + 1/4
4x + 5y = 3
5y = 3 - 4y
y = 3/5 - 4/5y
y = -4/5y + 3/5
The lines are not perpendicular because the slope of the second line is not the opposite of the original line.
Best of Luck!
