slope help

Question

Bob graphed a line that has a slope of -2. The line he graphed passes through the point (3,5). If Bob doubles the slope of his line and then shifts it down 1 unit, through which point will the line pass?

Answer 1

If you double the slope, then your new slope is -4.  Now if you draw the line with slope -2 and slope -4, you have a transformation in which the line rotates about a certain reference point.   You need to define that reference point.