The hanger is perfectly balanced meaning that both sides are the same. Since you want an equation that means there is going to be and equals sign indicating both sides are the same.
On one side there is 10 and a z dangling that means on the left 10+z will be the first part of your equation
On the other side, the right, there are four z's dangling at the same weight as the first side.
Z is unknown but can be solved for. The equation is the answer but if there is a follow up question asking to solve for z you would get
