Answer:
4d + 7n + 9y + 18
Explanation:
Add like terms, like terms are terms that have the same variable and power, For ex: 4d and 2d are like temrs so u can add them but 4d and 4d^2 are not cause they have different power(the ^2 thing).
(4d+9)+(7n-4)+(9y+5)
add like terms
4d + 7n + 9y + 18