Parallel lines have the same slope but a different y intercepts, because if you think about parellel lines, they'll never intersect-- if two lines have the same slope, that means they won't be able to intersect. However, if they have the same slope, they would be coinciding (the same). That's why the y intercepts are different.
Since the slope of the first line is -5/4, the slope for the line parallel to it would also be -5/4
27% decrease. If you divide 1102 from 806 you get 0.731. When you multiply this by 100 to find the percent (73.1) and then subtract it from 100 (100-73)you get the percent decrease(27)