solve the inequality -3n<81

Answer 1

divide by -3:

n > -27

Note that multiplying by a negative value changes the direction of the inequality. It's just shorthand for moving things to the other side:

-3n < 81

add 3n:
0 < 3n+81

subtract 81:
-81 < 3n

divide by 3:
-27 < n

which is the same as n > -27

Answer 2

mainly what you are trying to do is get the n by itself.