Complete the point-slope equation of the line through (6,4)and (7,2)

The slope is the change in y over the change in x, so it's (4-2)/(6-7)=2/-1=-2. Point slope form is y – y1 = m(x – x1), so we can plug in a point (6,4) to get 
y-6=-2(x-4)

Looks pretty good to me!