Slope-intercept form:
y = mx + b "m" is the slope, "b" is the y-intercept
For lines to be perpendicular, their slopes have to be the opposite/negative reciprocal (flipped sign and number)
For example:
slope is 2
perpendicular line's slope is -1/2
slope is -3/4
perpendicular line's slope is 4/3
#1: The slopes are the same, meaning they are parallel lines
#2: First isolate the "y" in the first equation
-4x + 5y = -5
5y = -5 + 4x
y = -1 + 4/5x They are not perpendicular because the slopes are 4/5 and -4/5
#3: Isolate "y" in the second equation
8y = 3x - 32
y = 3/8x - 4 They are perpendicular
#4: Isolate "y" is the 1st equation
10y = -9x
y = -9/10x They are parallel lines
The 3rd choice is your answer