What are the zeros for the function f(x) separate your solution using commas f(x)=(x-9)(x+1)

Galen sold tickets of his church’s carnival for a total of $2,820. children’s tickets cost $3 each and adult tickets cost $5 each. the number of children’s tickets sold was 30 more than 3 times the number of adult tickets slod. how many children’s ticket and how many adult tickets did he sell?

Someone answer this check out the image!

Ineed i been stuck on this question since yesterday