Perpendicular means the slope is the opposite inverse Lets re-organize the equation so its more friendly 4x-2y=9 -2y=-4x-9 y=2x+9/2 The slope of this is 2, so the opposite inverse would be -1/2 So far our new equation looks like y=-1/2x+b To find B we will input the coordinates (4,6) for their respective x,y values 6=-1/2(4)+b 6=-2+b b=8 y=-1/2x+8 The answer is B