Use the slope formula:-
[tex]\displaystyle\frac{y2-y1}{x2-x1}[/tex]
[tex]\displaystyle\frac{1-4}{0-5}=\frac{-3}{-5} =\frac{3}{5}[/tex]
Second pair:-
[tex]\displaystyle\frac{2-7}{-2-3} =\frac{-5}{-5} =1[/tex]
If we multiply/divide a negative by a negative, we get a positive. :)
Hope everything is clear; if you need any clarification/explanation, kindly let me know, and I will comment and/or edit my answer :)