SOLUTION: how do the y-coordinates change from (7,10) to (7,-2) in this translation?

The upper black dot is at (7,10) 

The lower black dot is at (7,-2) 



The upper black dot at (7,10) must fall twelve units to be where the

lower black dot is.  A fall of twelve units is indicated by -12.



Here's how to get that



end point's y-coordinate, -2, minus beginning point's y-coordiate, +10,



(-2)-(10) = -2-10 = -12 



The change in the y coordinate is -12.



Edwin