To find the slope of a line perpendicular to another line, we simply need to find the inverse negative of the slope of the first one. This makes sense if you visualize it on a graph or in your head.
The slope of the line given is -1/2.
To find the inverse negative we first inverse the number, then take then negatuve of that (or opposite order).
The inverse of -1/2 is, -2 (switch the numerator and denominator or do to the power of -1, ^-1).
The negative of -2 is, 2.
Therefore the slope of the line perpendicular to y = -1/2x + 5 is 2.