Can someone help me!

Geometry. i need step by step explanation on how to do each problem.

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?

For the following geometric sequence, find the recursive formula. {-80, 20, -5, } i need : ')