How to solve these, i feel like my teacher did not really cover these in class and i am having some trouble

I’m really confused and need to learn this

$5400 is? invested, part of it at 11? % and part of it at 8? %. for a certain? year, the total yield is ? $522.00. how much was invested at each? rate?

Show all work to identify the discontinuity and zero of the function f of x equals 6 x over quantity x squared minus 36