Answer:
-16n - 13
Explanation:
(2n-9) - (18n + 4)
1) Apply rule: (a) = a
= 2n - 9 - (18n + 4)
2) Apply the distributive law
= 2n - 9 - 18n - 4
3) Group like terms
= 2n - 18n - 9 - 4
4) Subtract the numbers
= 2n - 18n - 13
5) Add similar elements
-16n - 13