Perpendicular lines have slopes that are negative reciprocals, that is to say:
So, since your given equation is in slope-intercept form, you can determine the slope of the given line by inspection. Then calculate the negative reciprocal to get the slope of the desired line.
Next, use the point-slope form of an equation of a line to derive your desired equation:
where are the coordinates of the given point and is the calculated slope.
John
My calculator said it, I believe it, that settles it