First you should subtract 13 from -8. Then divide the answer by -3. Because you are dividing by a negative number, reverse the sign and you will get your answer.
13 - 3n < -8 -8 - 13 = ? -3n < ? ?/-3 = n
Like in this example, 3 - 5n < 13 13 - 3 = 10 -5n < 10 10/-5 = -2 n > -2
