Slope-intercept form:
y = mx + b "m" is the slope
First i would isolate the "y" in the equation.
2x + y = 4 Subtract 2x on both sides
2x - 2x + y = 4 - 2x
y = 4 - 2x or y = -2x + 4
The given line's slope is -2.
For lines to be perpendicular, their slopes have to be the opposite/negative reciprocals (flipped sign and number)
For example:
slope is 2
perpendicular line's slope is -1/2
slope is -2/3
perpendicular line's slope is 3/2
The given line's slope is -2, so the perpendicular line's slope is 1/2.
The 3rd option is your answer