[tex]7 - 5n = 42[/tex]
[tex] - 5n = 35[/tex]
[tex]n = - 7[/tex]
Since a negative times a positive makes a negative you can change your equation to 7 - 5n=42. You can now subtract 7 from both sides to get -5n = 35. Next get divide -5 on both sides giving you n = -7.
