Step-by-step explanation:
[tex]3x + 9 = 3( - 5) + 9 \\ = - 15 + 9 \\ = - 6[/tex]
3x+9 is equals to -6 , not more than based on the inequality, but it is lesser than 21.
However, the solution must fulfil both criteria to be a solution to the inequality. Therefore x = -5 is not a solution to the inequality.
