find the slope,if any, of the line perpendicular to the line through the points (2,-7) and (3,4).

i need to show my work!. i got 11 as my answer but i think its wrong.:(

The slope of the line joining those two points is (4+7)/(3-2) = 11

But, you are supposed to find the slope of any perpendicular line. That is -1/11.