Hey!
-----------------------------------------------------
The x-term has a coefficient of 2: 2x
The z-term has a coefficient of -1: -z
Together: 2x - z
The expression has a constant less than zero = 5 + 2z² (When it says a constant term less than zero you can assume that it can be any number being subtract by z).
Final Answer: 2x - z - 5 + 2z²
-----------------------------------------------------
Hope This Helped! Good Luck!