问题：
What is the equation of a line perpendicular to 3x
答案：
First, rearrange the equation into slope-intercept form, by subtracting 3x and-y from both sides: y=-3x+2 For two lines to be perpendicular, their slopes must be negative reciprocals. The negative reciprocal of-3 is 1/3. The problem also states that the perpendicular line has a y-intercept of 8. If you substitute 1/3 for m and 8 for b in the standard equation, you get